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TEACHERS'  MANUAL  OF  BIOLOGY 


THE  MACMILLAN  COMPANY 

NEW  YORK    .    BOSTON   •    CHICAGO 
DALLAS   •    SAN    FRANCISCO 

MACMILLAN  &   CO.,  LIMITED 

LONDON   •    BOMBAY  •    CALCUTTA 
MELBOURNE 

THE  MACMTLLAN  CO.  OF  CANADA,  LTD. 

TORONTO 


TEACHERS' 
MANUAL  OF  BIOLOGY 


A  HANDBOOK  TO  ACCOMPANY  THE   "APPLIED 

BIOLOGY"    AND    THE    "INTRODUCTION    TO 

BIOLOGY1'    BY    MAURICE    A.    BIGELOW 

AND  ANNA  N.  BIGELOW 


BY 


MAURICE    A.    BIGELOW 

» < 

PROFESSOR    OF    BIOLOGY"    IN    TEACHERS    COLLEGE 
COLUMBIA    UNIVERSITY 


gotk 

THE   MACMILLAN   COMPANY 
1912 


All  rights  reserved 


COPYRIGHT,  1912, 


J 


BIOLOGY 
ARY 


Bv  THE  MACMILLAN  COMPANY. 
Set  up  and  electrotyped.     Published  October,    1912 


INTRODUCTORY  NOTE 

THIS  Manual  for  teachers  has  been  prepared  in  order  to 
give  more  fully  than  was  possible  in  the  Applied  Biology 
for  students,  the  author's  suggestions  regarding  the  use  of 
that  book,  especially  in  many  cases  where  there  is  a  radical 
departure  from  the  usual  teaching  of  elementary  biological 
courses.  Moreover,  this  Manual  aims  to  be  of  help  to  biol- 
ogy teachers  whose  special  preparation  has  been  limited. 
Much  of  the  weakness  of  the  present-day  high-school  biology 
is  due  to  the  fact  that  the  majority  of  teachers  have  not 
critically  studied  the  integral  parts  of  the  courses  that  they 
are  trying  to  teach.  Textbooks  of  language  and  mathe- 
matics are  carefully  analyzed  for  the  teacher,  either  in 
appendices  or  in  separate  "  keys  "  ;  and  for  the  teaching  of 
biology  there  is  need  of  some  such  guide  to  give  specific 
advice  concerning  methods,  time,  materials,  relative  value, 
etc.,  in  teaching  difficult  topics. 

This  Manual  does  not,  in  any  way,  take  the  place  of  the 
"  Teaching  of  Biology  in  the  Secondary  School,"  by  F.  E. 
Lloyd  and  M.  A.  Bigelow,  published  by  Longmans,  Green, 
and  Company  in  1904.  That  work  deals  entirely  with 
general  principles,  while  this  is  concerned  with  the  detailed 
working  out  of  lessons  in  a  particular  type  of  elementary 
course  in  biology.  Wherever  possible  in  this  Manual,  spe- 
cific references  are  given  to  the  appropriate  discussions  in 
the  "  Teaching  of  Biology,"  thus  saving  the  time  of  teachers 
who  wish  to  refer  to  that  book. 

25111? 


vi  INTRODUCTORY  NOTE 

The  chapters  and  the  numbered  sections  of  this  Monn-i' 
correspond  with  those  of  the  Applied  Biology.  An  appm 
dix  in  the  Introduction  to  Biology,  which  is  in  preparation, 
will  contain  a  table  for  quick  reference  from  any  numbered 
section  of  the  Introduction  to  sections  of>tne  Applied  Biol- 
ogy and  of  this  Manual  that  deal  more^illy  with  the  same 
topics. 

A  list  of  books  for  teachers'  referenced  will  be  found  in  an 
appendix  to  this  Manual.  Authors'  nimes  are  arranged  in 
alphabetical  order,  and  the  date  of  publication  (copyright) 
of  each  book  is  added  to  avoid  contusing  past  or  future 
revised  editions.  References  to  this  list  are  by  names  and 
dates;  for  example,  Lloyd,  1904/49,  refers  to  page  49  of 
Tfie  Teaching  of  Biology,  by  Moyd  and  Bigelow ;  while 
Bigelow,  1904,  261,  refers  to  page  261  of  the  second  part  oi 
the  same  book,  which  has  entirely  independent  parts  f..i 
botany  and  zoology. 

The  index  to  this  Manual  will  make  it  useful  to  teachers 
who  are  not  working  with  th^  Applied  Biology,  but  who 
want  practical  points  concerning  the  teaching  of  topics  in 
other  textbooks.  If  the  Manual  is  used  for  this  purpose. 
the  corresponding  sections  of  the  Applied  Biology  should  be 
examined  at  the  same  time,  for  the  Manual  is  largely  a 
teachers'  supplement  to  the  accompanying  textbook. 

The  author  will  gladly  be  of  service  to  any  teachers  who 
use  this  Manual  or  the  Applied  Biology.  From  time  to 
time,  until  a  reprint  of  this  Manual  allows  supplementation, 
the  author  proposes  to  issue  mimeographed  sheets  contain- 
ing new  suggestions.  These  will  be  mailed,  without  charge, 
to  teachers  who  file  self-addressed  and  stamped  envelopes 
with  the  author.  Proper  credit  will  be  given  teachers  who 
send  helpful  criticisms  or  suggestions. 

The  authors  of  the  Applied  Biology  are  already  greatly 
indebted  to  the  following  biologists  who  have  given  sugges- 
tions that  are  incorporated  in  this  Manual:  Professor  \V. 


INTRODUCTORY  NOTE  Vll 

F.  Ganong,  of  Smith  College;  Professor  W.  S.  Hall,  of 
Northwestern  University  Medical  School;  Professor  E.  E 
Schuh,  of  Howard  University ;  Dr.  C.  Stuart  Gager,  Direc- 
tor of  Brooklyn  Botanical  Garden ;  Miss  Anna  M.  Clark,  of 
New  York  Training  School  for  Teachers ;  Professor  T.  D. 
A.  Cockerell,  of  Colorado;  Professor  John  Dearness,  of 

London,  Ontario. 

M.  A.  B. 

TEACHERS  COLLEGE, 
COLUMBIA  UNIVERSITY, 
May,  1912. 


CONTENTS 
y\ 

INTRODUCTORY  NOTE V 

CHAPTER 

I.     BIOLOGY  AS  A  SCIENCE,  §§  1-5    .         .        .        .        .  1 

II.     COMPOSITION  AND  CHANGES  OF  MATTER,  §§  6-11         .  4 

III.  CHARACTERISTICS  OP  LIVING  THINGS,  §§  12-31    .         .  7 

IV.  INTRODUCTION  TO  ANIMAL  BIOLOGY,  §§  32-64      .         .  16 
V.     INTRODUCTION  TO  PLANT  BIOLOGY,  §§  65-110      .         .  23 

VI.     COMPARISON  OP  ANIMALS  AND  PLANTS,  §§  111-122      .  36 

VII.     CLASSIFICATION,  §§  123-133 36 

VIII.     SEED-PLANTS,  §§  134-220 38 

IX.     SPORE-PLANTS,  §§  221-265     .......  61 

X.     PROTOZOA,  §§  266-279 58 

XI.      PORIFERA   AND    CtELENTERATA,    §§  280-292    ...  61 

XII.     "WORMS,"  §§  293-304 62 

XIII.  ECHINODERMS,  §§  305-308 64 

XIV.  ARTHROPODS,  §§  309-335       .        .         .        .         .        .65 

XV.     MOLLUSKS,  §§  336-342 70 

XVI.     VERTEBRATES,  §§  343-367 71 

XVII.     HUMAN  ANATOMY  AND  PHYSIOLOGY,  §§  368-447  .         .  81 

XVIII.     BIOLOGY  APPLIED  TO  HYGIENE,  §§  448-490  ...  91 

XIX.     EVOLUTION  AND  HEREDITY,  §§  491-503        .        .        .94 

APPENDIX  I.     DRAWINGS  AND  NOTES          .         .         .  96 

APPENDIX  II.     BIOLOGICAL  BOOKS  AND  PAMPHLETS  ...  98 
APPENDIX  III.     LABORATORY    EQUIPMENT,     MATERIALS,    AND 

METHODS     .......  102 

APPENDIX  IV.     A  YEAR'S  COURSE  IN  BIOLOGY         .        .        .105 


ix 


CHAPTER  I1 
BIOLOGY  AS  A  SCIENCE 

1.  Simple  classifying.  —  It  is  well  worth  while  to  ask 
young  students  to  write  in  parallel  columns  the  names  of 
various  living  and  lifeless  things.  Such  a  problem  will 
strike  many  teachers  as  absurdly  simple.  It  so  impressed 
the  writer  before  it  was  proved  by  many  trials  with  high- 
school  classes  that  most  students  can  profit  by  critical 
thinking  on  even  so  simple  a  classification  as  that  into 
living  and  lifeless.  The  problem  is  well  worth  five  minutes 
for  serious  consideration  by  the  students,  preliminary  to 
summarizing  by  the  teacher.  The  best  results  have  come 
when  the  teacher  placed  on  the  blackboard  the  names  of 
things  suggested  by  students,  arranging  them  in  columns 
for  lifeless  and  living.  As  a  side  issue,  it  is  worth  while 
to  help  the  young  students  do  some  simple  classifying; 
for  example,  many  lists  written  by  them  read:  "birds, 
robin,  chicken,"  or  "oak,  maple,  trees,"  or  even  "plants, 
sunflower,  corn."  In  all  such  cases  the  difference  be- 
tween specific  names  and  collective  names  of  groups  of 
natural  objects  should  be  made  clear  by  grouping  the 
specific  names  with  brackets  on  the  blackboard.  The 
writer  has  on  several  occasions  seen  many  minutes  prof- 
itably spent  on  such  simple  classifying,  which  the  students' 
notes  showed  was  needed.  Finally,  it  will  add  interest 
to  note  some  of  the  doubtful  cases,  such  as  dried  seeds 
capable  of  germinating ;  but  it  would  be  a  useless  exercise 

1  The  chapters  and  sections  of  this  Manual  are  numbered  to  correspond 
with  those  of  the  Applied  Biology. 

B  1 


2  TEACHER^   MANUAL  OF  BIOLOGY 

to  discuss  at  this  stage  whether  such  things  are  dead  or 
alive. 

3,  4.  Definitions  of  sciences.  —  At  the  outset,  students 
should  have  some  idea  of  the  field  of  any  new  study. 
Experience  shows  that  in  biology  they  cannot  be  left  to 
form  their  own  definitions.  Especially  should  teachers 
guard  against  the  common  tendency,  which  appears  even 
in  colleges,  to  use  zoology  and  biology  as  synonymous 
terms.  Emphasis  upon  §  4  in  the  Applied  Biology  will 
avoid  such  a  serious  misunderstanding. 

While  various  attempts  have  been  made  to  limit  the 
term  "biology"  to  special  usage,  such  as  to  bio-physiology, 
the  science  of  life-activities,  such  limited  use  no  longer 
need  be  regarded  so  far  as  general  education  is  concerned. 
The  word  "biology"  has  now  a  widespread  use  as  the 
general  term  including  the  fields  of  both  botany  and 
zoology,  and  biologists  must  invent  new  designations 
for  special  limited  aspects  of  the  general  field  of  biology. 

6.  Applied  biology.  —  This  paragraph,  in  the  Applied 
Biology,  includes  a  plea  and  defense  for  the  study  of  biology, 
and  is  an  anticipation  of  the  usual  question:  "Why 
should  I  study  animals  and  plants?"  Some  preliminary 
glimpse  of  the  outlook  of  biology  in  the  direction  of  human 
life  is  sure  to  be  helpful  to  many  students  who,  without 
some  idea  of  the  goal,  might  see  no  practical  meaning  in 
a  large  part  of  the  most  useful  subject-matter  of  biology. 
The  oft-commended  method  of  leaving  the  beginner  to 
develop  his  own  interest  in  biology  or  else  succumb, 
while  only  the  fittest  survive,  may  possibly  have  its  place 
in  the  training  of  special  workers  in  the  field  of  science; 
but  it  is  essential  that  high-school  biology  should  be  con- 
ducted so  as  to  awaken  in  the  students  the  greatest  pos- 
sible interest.  And  this  greatest  interest  is  all-important 
because  biology  is  so  variously  applicable  to  everyday 
human  life,  and  not  because  the  interest  of  students 


BIOLOGY  AS  A   SCIENCE  3 

means  the  professional  success  of  the  teacher.  The  wide- 
awake teacher  will  take  many  opportunities,  which  are 
opened  but  not  developed  in  other  parts  of  the  text- 
book, for  impressing  upon  the  students  the 'fact  that  the 
science  of  life  is  capable  of  extensive  application  in  the 
daily  life  of  all  citizens. 


CHAPTER  II 

COMPOSITION  AND  CHANGES  OF  MATTER 

6-11.  Essentials  of  chemistry  and  physics.  —  Since 
the  basis  of  correlation  in  the  Applied  Biology  is  physio- 
logical, it  follows  that  sonic  knowledge  of  the  elements 
of  chemistry  and  physics  is  necessary  for  the  students. 
In  many  schools,  and  in  some  elementary  text-books  of 
biology  and  physiology,  much  attention  is  given  to  an 
extended  series  of  chemico-physical  experiments  which 
are  introduced  in  the  first  part  of  the  course  of  biology  to 
be  studied  several  weeks  before  any  reference  is  made 
to  biological  problems  involving  hemistry  or  physics. 
The  objection  to  this  practice  is  th  t  the  students  forget, 
and  much  chemico-physical  teach  g  must  be  repeated 
when  needed  for  application  in  lysiology,  the  result 
being  wasteful  duplication.  For  e  jnple,  a  preliminary 
series  of  chemico-physical  lessons  on  foods  must  be  re- 
peated in  essentials  months  afterwards  when  digestion  is 
studied.  A  still  stronger  objection  to  such  preliminary 
work  is  that  a  close  correlation  in  time,  as  well  as  in  subject- 
matter,  makes  both  the  chemico-physical  facts  and  the 
biological  applications  more  intelligible  and  more  inter- 
esting. For  example  the  best  time  for  preliminary  lessons 
on  carbon  dioxide  is  when  a  biological  problem  such  a* 
respiration  calls  for  the  appropriate  chemical  facts. 

However,  there  are  certain  general  facts,  such  as  changes 
in  matter,  chemical  elements,  compounds,  etc.,  which 
are  not  called  for  in  biology  in  any  special  connection, 
and  which,  as  a  rule,  must  be  treated  as  preliminary  and 

4 


COMPOSITION  AND  CHANGES  OF  MATTER          5 

without  direct  application.  In  the  Applied  Biology  an 
attempt  has  been  made  to  select  such  material  for  Chapter 
II,  reserving  as  far  as  possible  the  chemico-physical  topics 
that  admit  of  close  correlation  with  the  biological  problems 
of  later  lessons.  The  sole  justification,  then,  for  Chapter 
II  is  that  it  presents  general  ideas  which  are  not  connected 
with  any  particular  lessons.  The  chapter  would  be  un- 
necessary if  all  students  could  study  elementary  chemistry 
before  biology. 

The  shorter  course,  Introduction  to  Biology,  will  include 
some  directions  for  simple  experiments,  because  it  is  as- 
sumed that  the  students  who  will  use  this  book  are  in 
the  early  years  of  high  school  and  probably  have  not 
had  any  chemistry  and  physics;  hence,  for  them,  the 
course  in  biology  must  be  made  an  introduction  to  science 
in  general.  This  is  in  harmony  with  the  widespread  idea 
that  science  in  the  first  year  of  high  schools  is  best  when 
presented  as  advanced  nature-study  and  as  an  intro- 
duction to  general  science,  with  human  life  as  the  center 
of  interest.  The  experiments  are  omitted  from  the 
longer  course  (Applied  Biology)  because  that  is  likely 
to  be  studied  in  high  school  later  than  the  first  year,  and 
it  is  probable  that  the  great  majority  of  the  students  will 
already  have  had  some  introduction  to  the  elements  of 
the  physical  sciences,  and  hence  the  text  of  Chapter  II 
will  be  more  or  less  of  a  review  of  familiar  facts  from  a 
new  viewpoint.  However,  the  experience  of  the  authors 
of  the  Applied  Biology,  and  that  of  other  teachers  who 
have  been  consulted,  has  been  that  very  many  high-school 
students  take  biology  before  chemistry  or  physics,  and  that 
most  of  those  who  have  previously  studied  these  sciences 
need  a  review  of  some  of  the  fundamental  ideas  that  are 
essential  for  the  physiological  phases  of  biology. 

7,  8.  Changes  of  matter.  —  The  authors  of  the  Applied 
Biology  realize  that  the  brief  definitions  of  chemical  and 


6  TEACHERS'  MANUAL  OF  BIOLOGY 

physical  change  in  terms  of  "composition"  of  matter  arc 
open  to  some  criticism  by  the  specialists  in  physical 
chemistry;  but  for  the  purposes  of  practical  life  and  of 
elementary  teaching  they  are  convenient  and  sufficiently 
accurate. 

9,  10.  Elements  and  compounds.  —  It  is  absolutely 
necessary  for  even  the  simplest  physiological  study  that 
students  have  general  ideas,  at  least,  regarding  elements 
and  their  part  in  the  formation  and  disintegration  of 
compounds.  Even  in  college  classes  of  biology  there 
are  frequently  students  who  have  not  studied  the  simplest 
chemistry  and  who  might  be  greatly  helped  even  by  such 
brief  and  superficial  outlines  of  the  essential  facts  as  are 
given  in  §§  9  and  10  of  the  Applied  Biology. 


CHAPTER  III 
CHARACTERISTICS  OF  LIVING  THINGS 

12.  Demonstration  method  for  practical  work.  —  As 
stated  in  the  Applied  Biology  in  a  footnote  belonging  to 
§  12,  some  of  the  practical  work  suggested  in  small  type 
throughout  that  book  is  most  satisfactory  when  demon- 
strated by  the  teacher.  In  most  elementary  courses  of 
biology  much  time  is  often  wasted  and  inaccurate  im- 
pressions given  the  students  by  individual  laboratory 
work  on  certain  topics. 

The  decided  advantages  of  demonstrations  for  some 
difficult  problems  are  as  follows :  (1)  Only  one  set  of 
apparatus  is  required.  (2)  The  teacher  may  be  reasonably 
sure  of  working  directly  to  the  correct  result,  while  a  large 
percentage  of  students  get  incorrect  results  from  their 
own  experiments.  (3)  The  teacher  can  make  sure  that 
all  students  in  even  a  large  class  have  seen  the  experi- 
ment correctly  worked  out,  while  this  is  impossible 
with  numerous  (20-40)  students  working  individually. 
(4)  Moreover,  the  teacher  can  lead  the  class  as  a  unit 
through  the  successive  steps  of  an  experiment  and  can  be 
certain  of  correct  observations  and  conclusions.  (5)  The 
demonstration  may  be  made  an  enormous  saver  of  time,  for 
often  an  energetic  instructor  can  in  ten  minutes  teach 
a  practical  lesson  to  the  great  majority  of  students  so 
that  they  comprehend  it  at  once  far  better  than  the 
exceptional  few  after  a  half  hour's  independent  work. 

The  common  objections  to  the  demonstration  method 
are  as  follows  :  (1)  Students  should  get  the  technical  training 

7 


8  TEACHERS'  MANUAL  OF  HIOLOGY 

from  performing  the  experiments  themselves.  One  answer 
is  that  it  is  better  for  them  to  get  scientific  training  from 
a  limited  number  of  problems  selected  because  it  is  reason- 
ably certain  that  the  average  pupil  can  solve  them  without 
waste  of  time.  Another  answer  is  that  the  average 
student  does  not  need  technical  training  in  laboratory 
methods,  but  needs  rather  the  information  and  point  of  view 
to  be  gained  from  a  well-selected  experiment.  (2)  Students 
are  said  not  to  "pay  attention"  to  demonstrated  experi- 
ments as  well  as  to  their  own  work.  This  is  because 
science  teachers  have  universally  adopted  a  device  for 
compelling  attention  in  the  individual  work.  That  device 
is  the  laboratory  notebook,  which  students  respect  be- 
cause it  is  destined  for  the  teacher's  inspection;  and  it 
should  be  applied  to  demonstrations  given  by  the  teacher. 
Every  student's  record  of  a  demonstration  should  give 
the  following :  (1)  statement  of  problem  to  be  solved  ; 
(2)' description  of  teacher's  method  of  attacking  the  prob- 
lem, with  labeled  sketch  of  apparatus  used;  (3)  results 
of  the  experiment;  (4)  conclusions  with  reference  to  the 
problem  to  be  solved,  or  what  the  experiment  has  proved. 
If  the  experiment  fails  to  give  definite  results,  record 
under  (3)  any  discoverable  factors  that  may  have  caused 
the  failure.  With  such  required  records  for  all  demon- 
strations, there  will  be  no  difficulty  in  securing  the  closest 
attention. 

After  careful  consideration  of  all  phases  of  the  problem 
of  demonstrations,  the  author  now  believes  that  it  is  far 
better  in  elementary  biology  to  put  into  demonstration 
form  all  difficult  practical  work  which  if  taken  up  as  in- 
dividual problems  means  failure  and  waste  of  time  for 
a  majority  of  the  average  students  in  large  classes. 

13.  Substitute  apparatus.  —  A  chemist's  ignition-tube 
(a  kind  of  test-tube  of  hard  and  thick  glass)  may  be 
stoppered  with  clay  through  which  is  inserted  a  small 


CHAEACTERISTICS   OF  LIVING   THINGS  9 

glass  tube  or  a  pipe  stem.  Or  the  teacher  may  use  a  short 
piece  of  gas-pipe,  iron  capped  at  one  end,  the  other  end 
stoppered  with  clay  packed  around  an  outlet  glass  tube 
or  pipe  stem. 

17.  Activities  of  living  things.  —  Experience  with 
this  lesson  has  shown  that  it  is  desirable  to  put  before  the 
students  at  this  stage  of  the  course  some  very  general 
ideas  concerning  the  life  of  animals  and  plants  in  order 
to  give  some  preliminary  view  of  problems  to  be 
worked  out  more  in  detail.  Without  such  a  preliminary 
survey,  the  students  must  work  blindly.  The  author  is 
well  aware  that  there  are  teachers  in  colleges  and  high 
schools  who  see  no  objection  to  working  blindly  for  weeks 
or  months,  with  the  expectation  of  giving  the  facts  some 
kind  of  an  interpretation  before  the  end  of  the  course ; 
but  such  a  practice  is  entirely  out  of  line  with  the  whole 
trend  of  modern  scientific  education.  The  strict  Agassiz 
method  of  leaving  a  student  to  work  through  a  maze  of  in- 
tricacies of  animal  and  plant  structure,  without  the  guidance 
of  a  definite  suggestion  as  to  what  he  is  working  for,  may 
have  made  or  discovered  a  few  great  biologists ;  but  imi- 
tation of  this  method  has  done  more  than  anything  else 
to  keep  high-school  and  college  biology  from  becoming, 
for  the  great  majority  of  students,  the  popular  subject 
that  its  content,  which  is  so  full  of  human  interest,  ought 
to  make  it. 

Biology  teachers  can  no  longer  afford  to  ignore  the  oft- 
repeated  criticism  by  intelligent  people  who  believe  in 
biology  for  the  purposes  of  liberal  education,  that  so 
much  work  commonly  assigned  in  biology  seems  to  be 
without  a  definite  goal  and  without  any  satisfactory 
meaning  to  students  after  the  work  has  been  .accom- 
plished. This  is  not  an  unfair  criticism  of  much  of  the 
common  laboratory  and  text-book  work,  especially 
morphological  lines.  It  is  greatly  to  be  desired 


10  TEACHERS'  MANUAL   OF  BIOLOGY 

that  high-school  biology,  and  perhaps  other  sciences, 
should  be  put  into  line  with  the  educational  principles 
that  have  been  successful  in  the  best  nature-study 
teaching  in  the  elementary  schools;  and  this  means 
developing  the  subject  logically  so  that  the  student  may 
see  in  advance  the  outlines  of  the  path  he  is  to  travel,  may 
understand  the  points  of  interest  as  he  passes  along,  and 
at  the  end  be  able  to  look  back  along  the  way  in  a  com- 
prehensive retrospect.  In  other  words,  the  student  has 
a  right  to  know  before,  during,  and  after  each  extensive 
exercise,  just  why  he  is  studying  that  particular  topic  of 
biology.  The  writer  must  confess  that  this  is  a  difficult  idea 
to  put  into  practice  at  all  times,  but  it  is  an  aim  well  worth 
careful  consideration  by  the  teacher  of  high-school  biology. 
The  lessons  in  §§  17-30  of  the  Applied  Biology  will 
undoubtedly  call  forth  the  criticism  that  abstract  generali- 
zations are  beyond  the  students.  The  author  replies 
that  the  avoidance  of  technical  language  makes  it  possible 
to  state  some  of  the  greatest  ideas  of  biology  in  very 
elementary  form.  It  will  probably  be  objected  by  some 
teachers  that  such  general  ideas  regarding  life-activities 
should  come  at  the  end  of  the  course,  after  the  students 
have  acquired  a  large  mass  of  facts  on  an  inductive  basis. 
This  view  is  plausible  in  theory,  but  critical  examination 
will  reveal  in  §§  17-30  little  requirement  for  a  basis  of 
induction  beyond  what  ordinary  observation  and  the 
nature-study  of  elementary  schools  may  be  expected  to 
give.  Moreover,  it  is  well  to  remember  that  the  strict 
use  of  the  scientific  method  is  very  limited  in  science 
teaching.  At  best  we  can  do  little  more  than  show 
students  a  point  at  a  time  in  one  animal  or  plant  type, 
and  then  tell  them  that,  so  far  as  is  known  in  present-day 
science,  the  same  thing  is  true  of  other  —  in  some  cases 
of  all  —  animals  and  plants.  (See  discussion  of  scientific 
method  in  biology  teaching  by  Bigelow,  1904,  pp.  299-309.) 


CHAEACTEEISTICS  OF  LIVING   THINGS  11 

In  order  to  get  the  greatest  possible  value  that  may  come 
from  study  of  such  general  considerations  after  the  students 
have  acquired  more  facts,  the  author  recommends  that 
§§  17-30  in  the  Applied  Biology  should  be  reviewed  just 
before  the  study  of  Chapter  VI ;  but  in  order  to  give  the 
students  some  outlook  for  Chapters  IV  and  V,  it  is  im- 
portant that  this  lesson  should  be  studied  before  pro- 
ceeding with  the  more  detailed  work  of  those  chapters. 

18.  Automatic  movement  is,  of  course,   not   absolutely 
distinctive,  if  we  plunge  deep  into  chemical  and  physio- 
logical  analysis.     Such  movement   of  the   animal   body 
is  due  to  chemi co-physical  changes  involved  in  getting 
the  energy  from  foods,  and  likewise  movements  in  some 
lifeless  things  are  due  to  similar  changes.     However,  such 
quibbles  of  advanced  physiology  have  no  place  in  elemen- 
tary teaching,  and  for  all  practical  purposes  the  power 
of  automatic  movement  is  strikingly  distinctive  of  life 
in  general  and  especially  of  animal  life.     Certainly  it  is 
the  presence  or   absence  of   automatic   movement  that 
enables  us  to  decide,  in  most^cases,  whether  an  animal  is 
dead  or  living, 

19.  Growth   and   assimilation.  —  The    common    state- 
ment in  college  text-books,  quoting  from  Huxley,  that 
stones  grow  by  accretion   (addition  of  particles  on  the 
outside),  while  living  things  grow  by  intussusception  (in- 
ternal interpolation  of  particles),  is  of  doubtful  use  in 
elementary  teaching.     It  is,  also,  not  strictly  true,  for 
there  are  cases  of  intussusception  in  lifeless  bodies  (Ver- 
worn,    General   Physiology,    1897,    p.    122).     Growth   by 
assimilation  deserves  more  emphasis  as  a  distinguishing 
characteristic,  because  this  is  so  closely  correlated  with 
the  familiar  knowledge  regarding  foods  of  animals  and  man. 
Of  course,  strictly  analyzing,  there  is  no  sharp  line  be- 
tween growth  of  inorganic  things  and  that  of  living  things ; 
for,  just  as  the  crystal  can  grow  only  from  the  same 


12  TEACHERS'  MANUAL  OF  BIOLOGY 

chemical  substance,  so  the  animal  grows  only  from  certain 
chemical  compounds  —  proteins,  carbohydrates,  fats, 
and  minerals.  These  four  different  foods  from  various 
sources  are  possibly  identical  in  the  analysis  of  chemistry, 
but  there  is  obviously  a  vast  difference  in  the  sum  total 
of  their  combinations  after  assimilation.  For  example, 
a  frog  and  a  bird  may  eat  earthworms,  but  however 
similar  in  chemistry  the  resulting  substances  may  be,  the 
important  fact  is  that,  viewing  the  result  in  the  living 
animals,  frog  substance  derived  from  earthworms  is  as 
different  from  the  bird  substance  derived  from  earthworms 
as  frogs  are  different  from  birds.  There  is  fundamental 
similarity  of  chemical  composition  of  frog  and  bird  but, 
aside  from  chemical  analysis,  the  two  animals  are  decidedly 
different.  These  strikingly  obvious  differences  are  what 
we  need  for  applied  biology  in  elementary  courses,  leaving 
the  quibbles  about  the  ultimate  similarities  and  differences 
in  chemico-physical  structure  to  the  advanced  student 
of  pure  science.  For  the  purposes  of  elementary  biology, 
it  is  sufficient  to  recognize  the  general  principle  illustrated 
when  a  frog  eats  earthworms  or  plants  and  assimilates 
the  unlike  material  to  form  substance  that  is  obviously 
frog  and  not  the  food  that  was  eaten. 

(D)  If  the  students  have  not  seen  experiments  with 
crystallization,  perhaps  in  the  physical  nature-study  of 
grammar  grades  or  in  introductory  physical  science,  it 
will  be  desirable  to  perform  the  experiments  suggested  in 
the  Applied  Biology  and  call  attention  to  the  main  facts 
that  illustrate  growth. 

20.  Breathing  of  frog.  —  The  word  respiration  is  de- 
liberately avoided  here.  In  the  present  connection  it 
is  undesirable  to  go  beyond  the  most  obvious  external 
manifestations  of  breathing. 

Lime-water  is  made  as  follows :  Slake  a  lump  of  freshly 
burned  lime  (calcium  oxide)  with  water.  Add  about 


CHARACTERISTICS  OF  LIVING   THINGS  13 

a  tablespoonful  of  the  freshly  slaked  lime  to  a  half-pint 
of  water,  in  a  stoppered  bottle,  and  after  a  day  pour  off 
the  clear  water  into  another  bottle,  or  filter  through 
coarse  filter-paper.  Drug  stores  sell  lime-water  for  use 
in  medicine  as  a  mild  alkali,  especially  used  in  milk  for 
small  children.  It  can  be  kept  for  some  time ;  but  before 
making  an  experiment,  a  small  quantity  should  be  tested 
by  pouring  into  a  test-tube  and  breathing  into  it.  A 
white  precipitate  should  form  quickly. 

Barium-water,  a  solution  of  barium  hydrate  (costing 
about  25  cents  per  pound  at  chemical  supply  houses), 
in  place  of  lime  as  directed  above,  is  more  convenient 
than  lime-water  for  testing  carbon  dioxide.  A  teaspoon- 
ful  of  the  barium  hydrate  will  make  a  quart  of  the  barium- 
water,  Make  a  solution  in  cold  water  in  a  stoppered 
bottle,  let  it  stand  a  day,  and  then  pour  the  clear  water 
into  another  bottle.  Keep  tightly  corked,  for  CO2 
from  the  air  will  soon  produce  a  cloudiness  due  to  precip- 
itation of  barium  carbonate. 

Carbon  dioxide.  —  It  does  not  seem  desirable  at  this 
stage  to  undertake  an  extended  lesson  on  carbon  dioxide. 
Simply  demonstrate  the  change  caused  by  breathing, 
name  the  substance  that  is  precipitated  in  the  limewater, 
and  leave  the  discussion  of  carbon  dioxide  and  its  proper- 
ties until  the  chemistry  of  respiration  is  reached  in  later 
lessons. 

The  explanation  that  the  white  precipitate  is  calcium  car- 
bonate in  the  lime-water,  or  barium  carbonate  in  the  barium- 
water,  formed  by  a  combination  of  C02  and  the  hydroxide, 
is  interesting  to  pupils  who  have  studied  some  chemistry. 

The  presence  of  carbon  dioxide  in  the  air  of  the  school- 
room may  be  demonstrated  by  pouring  some  barium- 
water  into  a  shallow  glass  dish  and  leaving  it  exposed  to 
the  air  for  an  hour  or  two.  A  white  film  usually  forms 
in  a  short  time. 


14  TEACHERS'   MANUAL   OF  BIOLOGY 

Control  experiments.  —  The  experiment  with  the  frog 
gives  the  first  good  opportunity  for  a  "control,"  i.e., 
an  exactly  parallel  experiment  without  an  important 
factor  (in  this  case  a  frog),  and  serving  to  prove  by  com- 
parison that  the  omitted  factor  is  responsible  for  the  result. 
Such  "  controls  "  should  be  made  whenever  possible.  In  §  26 
on  plant  breathing,  there  is  the  same  need  of  a  "control." 

Even  such  a  simple  experiment  as  breathing  through 
a  straw  into  lime-water  does  not  in  itself  prove  that 
breathed  air  is  changed ;  we  must  show  that  fresh  air 
does  not  cause  a  precipitate  in  lime-water.  This  may  bo 
proved  by  shaking  some  lime-water  in  a  jar  filled  with 
fresh  air,  or  by  pumping  such  air  into  lime-water  with  a 
pair  of  bellows  or  an  atomizer.  The  great  value  in  all 
scientific  experiments  lies  (a)  in  imparting  information 
in  the  most  impressive  way  known  to  educators,  and  (b)  in 
leading  students  to  logical  thinking.  The  relative  values 
of  these  two  results  are  not  yet  known  (see  Bigelow, 
1904,  pp.  244-259) ;  but  certainly  no  opportunity  for 
logical  work  should  be  omitted.  Hence  it  is  important 
that  the  teacher  should  go  over  each  experiment  and  ex- 
plain each  step  and  what  it  proves.  Herein  is  the  great 
value  of  "controls,"  for  they  alone  teach  the  nature  of 
scientific  proof. 

In  many  parts  of  the  Applied  Biology  the  authors 
have  been  forced  by  space  limitations  to  omit  detailed 
directions  for  "control"  experiments. 

24.  Moving  protoplasm.  —  Leaflets  of  Elodea  (also 
known  as  Anacharis),  the  staminal  hairs  of  Tradescantia 
virginica,  the  l^nets  and  internodal  regions  of  Nitella  and 
Chara,  and  rcj^hairs  of  rye  and  other  seedlings  grown 
on  moist  paper  may  be  used  for  demonstrating  move- 
ments of  protoplasm.  In  Elodea  the  large  chlorophyll- 
bodies  (chloroplasts)  are  carried  around  with  the  moving 
protoplasm ;  but  in  Nitella  and  Chara  they  arc  station- 


CHARACTERISTICS   OF  LIVING   THINGS  15 

ary  in  the  peripheral  layer  of  protoplasm.  Mount  leaflets 
in  fresh  water,  cover,  and  use  about  100  magnification. 
It  may  be  necessary  to  examine  several  leaflets  of  Elodea 
before  finding  very  transparent  cells,  and  the  Nitella  and 
Chara  plants  are  often  incrusted  with  lime  deposits. 
Also,  the  movements  often  cease  temporarily  when  the 
plant  leaflets  are  first  mounted  or  if  subjected  to  jar  or 
pressure. 

Reference  to  Fig.  30  in  1911  edition  should  read  Fig.  28. 

25.  "Plant  food."    -  The  suggestion  in  this  section  that 
soil  fertilizers  contain  some  food  for  plants  is  open  to 
objection  from  the  viewpoint  of  strict  physiology;    but 
the  popular  usage  of  the  phrase  " plant  food"  is  necessary 
for  this  preliminary  survey  of  plant  activities.     (See  §  97 
in  this  Manual.) 

26.  "Plant    breathing." —The     word     "breathe"     is 
popular  and  not  scientific,  and  is  sufficiently  accurate  for 
our  present  lesson.     The  strict  botanist  will  insist  upon 
the  use  of  " respire";    but  this,  too,  is  not  without  its 
possibilities  of  confusion.     (See  §  51  in  this  Manual.) 

(D)  If  the  experiment  with  a  potted  plant  under  a 
bell-jar  is  performed,  a  " control"  without  the  plant 
should  be  demonstrated.  Also,  the  bottom  of  the  jar 
should  be  sealed  to  a  glass  plate  with  vaseline,  or  set  on 
a  dinner-plate  containing  a  half-inch  of  water.  The  ex- 
periment must  be  carried  on  without  light  (reserve  expla- 
nation to  students  of  influence  of  light  until  §§  99-102). 
Jars  may  be  wrapped  with  black  cloth  or  paper.  A 
wooden  box  (about  18"  cube),  painted  inside  with  lamp- 
black mixed  with  turpentine  and  little  ^toio  linseed  oil, 
and  with  large  ventilating  holes  covered  if  ^)ose  curtains 
of  black  cloth,  is  a  useful  piece  of  apparatus  for  experi- 
ments requiring  absence  of  light.  In  above  experiment, 
cover  the  bell-jar  with  the  box. 

Another  method  is  described  in  §  106  in  this  Manual. 


CHAPTER  IV 
INTRODUCTION  TO  ANIMAL  BIOLOGY 

32-64.  Order  of  study.  —  The  text  of  this  chapter  in 
the  Applied  Biology  has  been  arranged  so  that,  if  the 
teacher  prefers,  it  may  follow  the  introduction  to  plant 
biology  (Chapter  V).  The  reasons  for  such  a  change 
in  the  order  of  study  might  be  (1)  the  greater  ease  of 
collecting  certain  plant  materials  in  early  autumn,  and 
(2)  the  claim  of  relatively  few  teachers  that  plants  are 
better  for  beginning  the  study  of  biology. 

When  functions  are  to  be  considered  and  the  course  is 
really  more  than  advanced  nature-study,  it  is  probably 
far  better  to  begin  with  an  animal,  because  comparison 
with  the  human  body  makes  an  easier  way  to  the  intro- 
duction of  physiological  principles  that  apply  to  organ- 
isms in  general.  However,  it  is  desirable  that  teachers 
should  try  each  order  of  beginning  the  study  with  classes 
in  different  years  or  school  terms. 

If  the  preference  of  the  teacher  or  availability  of  ma- 
terials favor  plant  study  in  the  autumn,  there  will  be  no 
difficulty  in  taking  up  Chapter  V  after  I,  II  and  III, 
and  then  later-stucTying  IV.  See  note  in  §  65  of  this 
Manual. 

Frog  as  a  type.  —  In  the  lessons  of  Chapter  IV  the 
frog  should  be  studied  as  a  type  of  animal  structure  and 
functions,  not  simply  as  an  amphibian.  Hence  the 
teacher  should  emphasize  those  points  in  which  the  frog 
illustrates  animals  in  general,  or  ;i1  least  the  backboned 
animals.  Those  who  do  not  appreciate  the  fact  that 

16 


INTRODUCTION   TO  ANIMAL  SlOLOGY  17 

study  of  one  animal  may  teach  much  general  zoology 
should  read  at  least  the.  first  chapters  of  Huxley's  The 
Crayfish  as  an  Introduction  to  the  Study  of  Zoology  —  one 
of  the  great  zoological  classics. 

The  teacher  who  is  preparing  to  present  Chapter  IV 
will  do  well  to  become  familiar  with  the  first  part  of 
Parker  and  Parker's  Practical  Zoology,  or  with  Holmes's 
Biology  of  the  Frog. 

32.  The  value  of  the  frog  for  introductory  type  study 
is  discussed  by  Bigelow,  1904,  pp.  360,  370,  and  378; 
and  suggested  outlines  for  such  work  are  given  on  pp. 
386-388  of  the  same  book.  The  authors  of  the  Applied 
Biology  believe  that  the  students  ought  to  know  in  ad- 
vance "why  the  frog  is  selected  for  study."  /(See  §  5  in 
this  Manual.)  . 

In  a  short  course  where  there  can  be  dissection  of  but 
one  animal,  it  is  worth  while  to  make  an  extra  effort  to 
obtain  frogs  for  that  work.  Even  if  it  is  possible  to  get 
but  one  frog  for  each  group  of  four  students,  the  authors 
have  found  that  very  satisfactory  work  can  be  done 
under  these  conditions;  and  rather  than  omit  the  frog 
because  not  enough  are  available  even  for  these  groups, 
the  authors  advise  that  the  pupils  use,  in  connection  with 
the  text,  specimens  formerly  dissected  by  the  teacher 
and  preserved.  In  such  an  event,  it  will  be  well  later  to 
let  the  students  dissect  a  fish,  in  order  to  give  them  some 
practice  in  individual  laboratory  work. 

34.  Defense  of  animal  study  has  been  found  useful  (1)  in 
order  to  overcome  the  natural  repugnance  of  many  stu- 
dents to  work  in  dissection,  and  (2)  because  it  is  a  splendid 
opportunity  for  calling  attention  to  some  facts  that  will 
tend  to  make  the  students  have  a  sane  view  of  the  scien- 
tific study  of  animals.  In  these  days  of  anti- vivisection 
crusades,  led  usually  by  people  who  forget  or  have 
never  known  the  unnecessary  killing  and  cruelty  to  ani- 


18  TEACHERS*  MANUAL   OF  JUOLOGY 

mals  by  hunters  and  others,  and  who  are  blissfully  igno- 
rant of  the  results  and  methods  of  biological  science, 
it  is  important  that  those  who  study  even  the  elements 
of  biology  should  become  acquainted  with  facts  that  will 
give  a  sensible  attitude  towards  scientific  study  and  at 
the  same  time  towards  other  problems  that  arise  from 
man's  dominion  over  animals. 

35.  Material  for  study  of  frog.  —  It  is  best  to  keep 
living  frogs  (see  Bigelow,  1904,  p.  410),  and  chloroform 
them  a  half-hour  before  needed  for  study.     The  work 
cannot  be  completed  in  one  day,  and  specimens  should 
be  preserved  hi  water  containing  a  small  amount  of  car- 
bolic acid,  or  other  antiseptic. 

If  frogs  must  be  preserved  in  the  autumn,  alcohol  is 
better  than  formalin  for  females,  because  the  latter 
causes  swelling  of  oviducts  (see  note  by  Bigelow,  1904, 
p.  408).  Denatured  or  wood  alcohol  will  answer  all 
purposes,  if  a  school  does  not  use  enough  in  its  science 
departments  to  warrant  buying  pure  alcohol  in  bonded 
barrels. 

The  comparison  of  frog  and  human  with  reference  to 
dorsal,  etc.  (p.  26),  should  also  state  that  in  modified 
animals  the  lower  surface  is  not  always  ventral,  e.g.,  a 
flounder  lies  on  its  side. 

36.  Frog's  heart.  —  The  phrase  "the  posterior,  conical, 
whitish  part  of  frog's  heart  is  the  ventricle"  refers  to  the 
dead  specimen,  in  which  the  ventricle  is  contracted  and 
empty  of  blood.     Of  course,  it  is  reddish  when  full  of 
blood. 

Frog's  bladder.  —  A  specimen  showing  the  bladder 
(p.  35  in  Applied  Biology)  may  be  prepared  as  follows : 
Select  a  frog  and  kill  it  v;'th  chloroform  or  ether. 
Carefully  cut  open  the  frog's  abdominal  wall,  tie  a  thread 
around  the  large  intestine,  and  then  with  a  medicine- 
dropper  inject  water  containing  some  lamp-black,  or 


INTRODUCTION  TO  ANIMAL  BIOLOGY  19 

other  pigment,  into  the  cloaca  so  as  to  distend  the  bladder. 
The  specimen  may  be  preserved  for  years  in  five  per  cent 
formalin  solution. 

Circulation  in  capillaries.  —  For  demonstrating  this  in 
a  tadpole's  tail  (p.  32  in  Applied  Biology),  use  a  glass 
plate  such  as  a  3  X  4  photographic  negative  that  has 
been  cleaned ;  or,  which  is  much  better,  use  the  cover  of 
a  Petri  dish  (commonly  used  for  bacteria,  §  245) ;  or  a 
watch-glass  with  a  flat  bottom.  Lay  the  tadpole  on  its 
side,  pour  a  few  drops  of  water  on  its  tail,  cover  its  head 
and  body  with  a  piece  of  water-soaked  cotton,  and  adjust 
the  glass  on  the  stage  of  the  microscope.  Use  low  power. 
As  a  rule,  the  tadpole  will  lie  quietly  for  some  time. 

If  tadpoles  are  not  available,  the  web  of  a  frog's  foot 
may  be  used  to  demonstrate  the  capillary  circulation. 
Take  a  thin  board  about  three  inches  wide  and  eight 
inches  long,  and  bore  a  half -inch  hole  about  two  inches 
from  one  end.  Select  a  small  frog  (one  with  an  unpig- 
mented  web  on  a  hind  foot,  if  possible) ;  wrap  the  body 
with  a  strip  of  very  wet  cloth;  fasten  the  body  to  the 
board  by  means  of  small  rubber  bands;  catch  some 
loops  of  threads  around  the  tips  of  the  toes;  and  draw 
the  threads  so  as  to  spread  the  web  over  the  hole.  The 
threads  are  most  easily  fastened  by  drawing  them  beneath 
some  slivers  previously  raised  with  a  knife  at  the  edges 
of  the  board;  but  common  pins  may  be  used.  Now 
clamp  the  board  on  the  stage  of  the  microscope  with  the 
hole  placed  so  that  light  will  be  reflected  through  the 
stretched  web.  If  the  frog  struggles  violently,  pour  a 
few  drops  of  sulphuric  ether,  or  chloroform,  on  a  small 
piece  of  cotton  and  place  over  the  nostrils  until  the  ani- 
mal becomes  quiet.  The  frog  should  be  released  and 
returned  to  an  aquarium  as  soon  as  possible,  in  order  not 
to  keep  it  long  in  a  position  that  many  students  will  think 
more  uncomfortable  to  the  frog  than  it  probably  is. 


20  TEACHERS'  MANUAL  OF  BIOLOGY 

Teachers  of  elementary  zoology,  particularly  in  public 
schools,  should  aim  to  avoid  criticism  by  those  who  hold 
extreme  views  on  the  question  of  cruelty  to  animals. 

38.  Study  of  microscope.  —  The  author  of  this  Manual 
will  gladly  loan  to  any  reader  who  sends  a  self-addressed 
envelope  nine  or  ten  inches  long,  a  sample  set  of  type- 
written sheets  for  a  lesson   (one  hour)  on  microscopes, 
which  is  required  of  all  beginners  at  Teachers  College, 
Columbia  University,  before  they  go  on  to  study  tissues. 
Pictures   of   microscopes   cut   from   old   catalogues   and 
mounted  on  cardboard,  the  chief  parts  being  labeled,  are 
used  to  illustrate  the  typewritten  directions.     The  lead- 
ing manufacturers  of  microscopes  will  send  their  cus- 
tomers booklets  on  how  to  use  the  microscope,  and  some 
of  them  will  also  supply  a  wall-chart. 

38-41.  Preparations  needed  for  most  of  this  introduc- 
tion to  microscopic  study  may  be  made  from  fresh  ma- 
terials. Some  permanent  preparations  are  desirable. 
Teachers  who  lack  training  in  microscopic  technique  will 
find  some  general  directions  in  Parker  and  Parker's 
Practical  Zoology,  pp.  121-125,  135-139.  Those  wishing 
to  learn  the  special  technique  should  read  Guyer's  Animal 
Micrology  (University  of  Chicago  Press),  and  similar 
books  by  Gage,  Lee,  and  others.  (Listed  by  Bigelow, 
1904,  p.  393.) 

Preparations  may  be  purchased  from  dealers  named  in 
Appendix  III  of  this  Manual,  and  from  others  listed  by 
Bigelow,  1904,  pp.  414^16. 

39.  Epidermis  of  frog.  —  Two  or  three  frogs  kept  for  a 
few  hours  in  a  small  aquarium  or  battery-jar  will  usually 
rub  off  large  sheets  of  their  epidermis.     Collect,   wash 
well,  and  preserve  in  strong  alcohol.     Almost  any  aniline 
dye  dissolved  in  alcohol   or  water  will  stain  the  cells. 
Ordinary  red  or  green  ink  diluted  with  water  also  works 
well,  if  special  stains  are  not  at  hand. 


INTRODUCTION  TO  ANIMAL  BIOLOGY  21 

41.  Concerning  moving  protoplasm  see  §  24  in  this 
Manual. 

42-55.  Beginning  physiology.  —  These  sections  in  the 
Applied  Biology  are  intended  as  a  general  introduction  to 
the  elements  of  animal  physiology.  The  relation  of  such 
an  approach  to  human  physiology  is  discussed  by  Bigelow, 
1904,  pp.  272-275,  459,  462-464.  In  such  a  preliminary 
survey  as  that  given  to  the  frog  in  §§  42-55,  it  seems  best 
to  avoid  details ;  e.g.,  digestion  is  described  as  caused  by 
secretions,  which  are  not  named  and  located  in  this 
chapter. 

45.  Absorption.  —  The  experiment  with  blotting  paper 
is  a  case  of  nitration  and  only  suggestive,  for  osmosis  is 
involved  in  absorption  in  the  digestive  organs  of  animals. 
However,  the  same  result  might  be  obtained  by  osmosis 
through  several  layers  of  parchment  or  other  membrane 
that  allows  true  osmosis. 

51.  Breathing.  —  Some  authors  prefer  to  limit  the 
word  "breathing"  to  the  mechanical  or  muscular  work 
of  pumping  air  into  and  out  of  the  lungs,  and  not  as  a 
popular  synonym  for  respiration;  but  it  seems  doubtful 
whether  science  can  compel  a  strictly  scientific  usage  of 
such  a  popular  word,  and  for  accurate  purposes  it  is 
better  to  use  the  term  "  respiration."  It  is  still  better, 
in  the  opinion  of  the  writer,  to  recognize  that  respiration 
is  an  old  term  combining  and  complicating  two  processes 
(viz.,  oxygen  supplying  and  carbon  dioxide  excretion) ; 
and  hence  in  the  Applied  Biology  these  are  treated  sepa- 
rately in  §§  48,  50,  105,  106,  425-431,  433. 

Respiration.  —  In  treating  oxygen-supply  and  excretion 
of  carbon  dioxide  in  separate  sections,  the  authors  are 
aware  of  a  rather  radical  departure  from  the  usual  presen- 
tation; but  many  years'  trial  with  both  high-school  and 
college  classes  has  led  to  the  conviction  that  much  clear- 
ness is  gained  by  avoiding  the  time-honored  confusion 


22  TEACHER*     MAXTAL    OF   Hl()L<K,y 

involved  in  considering  respiration  as  one  function  with 
two  opposed  processes.  Because  the  lungs  happen  to 
perform  two  processes  at  the  same  time  is  no  logical 
argument  for  treating  such  processes  together  and  thereby 
confusing  them.  A  human  hand  may  wield  a  hammer  or 
work  a  piano,  but  the  doing  of  two  kinds  of  work  by  this 
same  organ  is  no  reason  why  blacksmithing  and  piano- 
playing  should  be  studied  together. 

Of  course,  the  fact  that  there  is  a  complementary  rela- 
tion between  the  amount  of  oxygen  absorbed  and  of  car- 
bon dioxide  excreted  is  a  reason  for  considering  them 
together,  but  this  is  a  problem  for  advanced  study,  rather 
than  for  the  high  school. 

See  note  on  §  100. 

62.  The  transporting  work  of  blood  with  regard  to  foods, 
oxygen  (§  48)  and  excretions  (§  50),  needs  frequent 
emphasis.  Of  course,  lymph  in  the  frog  also  plays  a 
part  in  the  same  functions;  and  might  be  described  in 
connection  with  this  section  (see  §  408  in  Applied  Biology). 

66-62.  Frog  development.  —  As  introductory  to  this 
lesson,  review  §§  21  and  22.  It  is  advisable  to  have 
material  in  formalin  for  illustration,  but  living  frog's 
eggs  should  be  followed  through  their  development  in 
early  spring.  Of  course,  details  of  the  cleaving  egg, 
formation  of  germ-layers,  etc.,  do  not  belong  in  elemen- 
tary work. 

69.  Reference  to  eFigs.  A,  B,  C,  D  (bottom  of  p.  59  in 
Applied  Biology)  should  read  Figs.  22,  A,  B,  C,  D. 


CHAPTER  V 

INTRODUCTION  TO  PLANT  BIOLOGY 

66-110.  Order  of  study.  —  If  the  course  begins  in 
September,  some  teachers  may  prefer  to  make  use  of 
plant  materials  available  then.  This  may  be  done  by 
assigning  this  chapter  subsequent  to  Chapters  I,  II  and 
III,  and  then  either  taking  Chapters  IV,  VI,  VII  and 
VIII,  in  this  order,  or  (less  desirable)  following  Chapter  V 
with  Chapters  VIII  and  IX.'  The  authors  believe  that 
Chapters  IV,  V,  VI  and  VIII  will  be  found  so  arranged 
that  any  one  of  these  orders  of  study  may  be  easily  fol- 
lowed. See  also  note  in  §  32  of  this  Manual. 

The  terms  "flowering"  and  "flowerless"  are  deliber- 
ately used  in  §  65,  because  at  this  stage  they  will  convey 
more  meaning  to  the  students  than  would  any  other 
words.  This  is  certainly  not  the  time  to  introduce 
beginners  to  terms  such  as  phanerogams,  spermatophytes, 
and  cryptogams,  concerning  the  use  of  which  even  the 
botanists  disagree. 

65.  Comparative  botany  for  beginners.  —  Judging  from 
the  majority  of  text-books  of  elementary  botany  and 
especially  from  the  most  successful  >ries,  the  approved 
and  highly  orthodox  way  of  begimr  he  scientific  study 
of  plants  is  to  make  a  series  of  is  of  seeds,  stems, 

roots,  flowers,  etc. ;  and  wi  \  of  these  specimens 

to  plunge  a  beginner  into  the  m  , •,.  01  v,omparative  botany. 
The  student  first  compares  com  aim  seeds  with  seeds  of 
perhaps  a  half-dozen  plants  he  h  never  seen;  then  he 
is  pushed  on  to  make  a  compara,  study  (morphologi- 

23 


24  TEACHERS'  MANUAL  OF  BIOLOGY 

cal)  of  roots  of  unfamiliar  plants;  and  so  on  through  tin- 
collections  of  stems,  leaves,  flowers  and  fruits.  The  final 
outcome  in  the  mind  of  the  student  is  supposed  to  be  a 
sort  of  composite  photograph  of  the  best  that  it  is  good 
to  know  about  plants  and  their  life.  This  is  certainly  a 
result  to  be  desired ;  but  the  trouble  is  that  few  average 
students  ever  put  these  stray  ideas  together  and  thus  get 
a  clear  conception  of  the  interrelations  of  the  various 
organs  of  a  plant  considered  as  a  living  individual.  In 
fact,  the  students  really  do  not  know  any  one  plant,  but 
rather  a  mass  of  disjointed  pieces  of  plants.  After  much 
critical  observation,  experimentation  and  reading  of 
examination  papers,  the  authors  of  the  Applied  Biology 
are  convinced  that  few  beginners  get  from  such  compara- 
tive botany  as  clear  an  idea  of  the  life  of  a  plant  as  they 
often  get  in  the  same  length  of  time  from  the  study  of 
animals.  The  difficulty  seems  to  be  connected  with  the 
intense  comparative  study  of  plant  parts  before  the  stu- 
dents have  been  prepared  for  such  work.  Comparing 
this  method  of  beginning  botany  with  the  common  order 
of  beginning  zoology,  it  is  evident  that  the  very  nature 
of  animal  materials  has  tended  to  force  well-rounded 
studies  of  at  least  one  type  of  animal,  before  an  attempt 
at  comparing  several  animals  is  made.  Even  a  botanist 
who  teaches  beginning  botany  comparatively  would  con- 
sider it  absurd  for  a  zoologist  to  make  collections  of  heads, 
legs,  hearts,  stomachs,  etc.,  and  then  to  proceed  to  teach 
beginners  by  having  them  spend  a  week  or  more  in  com- 
paring all  available  legs,  then  a  week  on  the  study  of 
typical  heads,  hearts,  stomachs,  and  so  on  in  imi- 
tation of  the  seed-root-stem-leaf  plan,  comparing  in- 
tensively the  various  types  of  each  organ  before  the  stu- 
dents know  the  meaning  of  that  organ  in  the  structure 
and  life  of  at  least  one  animal.  The  very  suggestion 
sounds  absurd  to  a  zoologist,  and  so  it  is ;  but  it  is  prac- 


INTRODUCTION  TO  PLANT  BIOLOGY  25 

tically  just  what  we  have  long  considered  proper  for 
beginning  botany.  Probably  the  chief  reason  for  the 
wide  adoption  of  this  order  in  botany  is  that  it  is  easy 
to  go  out  and  collect  a  lot  of  leaves,  stems,  or  flowers; 
but  it  is  not  at  all  easy  to  assemble  a  set  of  legs,  hearts, 
or  stomachs  of  animals. 

Comparative  study  in  beginning  botany  received  a 
powerful  impetus  in  the  earlier  teaching  from  the  system- 
atic point  of  view  (e.g.,  Gray's  Lessons  in  Botany),  and 
the  convenience  of  materials  has  tended  to  perpetuate 
the  method  long  after  the  point  of  view  has  changed 
decidedly. 

The  arguments  (see  Bigelow,  1904,  pp.  352-355)  for 
general  study  of  an  animal  type  as  an  introduction  to 
zoology  are  certainly  applicable  to  botany.  In  fact,  the 
plan  has  been  worked  out  for  a  plant  in  Sedgwick  and 
Wilson's  General  Biology,  which  in  its  general  outlines 
must  appeal  to  every  one  who  has  the  point  of  view  of 
general  biology,  even  though  one  may  question  whether 
the  fern  as  a  type  is  the  best  available  plant  (Lloyd, 
1904,  p.  114). 

The  study  in  Chapter  V  of  the  Applied  Biology  is  planned 
to  introduce  plant  biology  along  lines  parallel  with  those 
adopted  in  the  previous  chapter  for  animal  biology.  It 
will  be  obvious  to  the  critical  reader  that  in  certain  cases 
the  detailed  treatment  has  been  made  from  the  view- 
point of  zoology  rather  than  from  the  viewpoint  that 
prevails  in  most  text-books  of  elementary  botany.  As 
an  example  may  be  cited  the  physiological  topics  under 
headings  parallel  with  those  applied  to  the  animal  side. 
The  writer  urges  as  a  justification  for  this  the  fact  that 
the  greatest  interest  in  the  study  of  biology  is,  for  the 
average  citizen,  gained  by  viewing  it  from  the  standpoint 
of  animals  (discussed  by  Bigelow,  1904,  p.  252) ;  and  there- 
fore in  order  to  develop  the  greatest  value  from  plant 


Jii  TEACHERS'   MANUAL   OF  BIOLOGY 

study,  the  presentation  of  facts  must  be  harmonized  as 
far  as  possible  with  those  on  the  animal  side,  which  in 
turn  have  a  bearing  upon  the  human  aspect  of  biology. 

66-81.  Bean  plant  for  introductory  study.  —  After  much 
search  for  a  plant  adapted  to  a  study  parallel  with  that 
of  the  animal  in  the  preceding  chapter,  the  bean  plant 
was  selected.  It  was  used  by  Huxley  and  Martin  in  their 
Practical  Biology,  and  is  recommended  by  Ganong,  who 
says  (1899,  p.  194)  that  "the  advantage  of  following  some 
one  kind  of  plant  through  the  entire  cycle  is  very  great." 

66.  Bean  plant.  —  Materials  :  young  bean  plants,  some 
three  and  some  five  weeks  from  beginning  of  germina- 
tion, four  or  five  inches  high,  some  growing  in  pots  or 
boxes.  Some  may  be  preserved  in  fruit-jars  with  two  to 
five  per  cent  formalin  solution.  Also  have  some  plants 
in  flower  and  pod.  These  can  be  grown  in  six  or  eight 
weeks  by  planting  some  "extra  early"  variety  (see  seed 
catalogues).  Also  have  bean  plants  growing  in  pots,  or  at 
least  museum  specimens  (in  formalin)  of  such  plants,  from 
seeds  planted  one  inch  deep  and  others  four  inches  deep, 
some  three  weeks'  growth  and  some  six  weeks'  growth. 

Reference:   "Beans"  (Farmers'  Bulletin  289). 

68.  Roots.  —  Flower-pot  saucers  are  excellent  for  grow- 
ing roots  and  root-hairs.     See  Ganong,  1910,  342,  343. 

Strictly  speaking,  only  the  cell-walls  containing  proto- 
plasm and  nuclei  are  complete  cells,  as  defined  on  pages 
40  and  41 ;  and  the  honeycombed  appearance  in  the 
center  of  sections  of  roots  and  stems  is  due  to  empty  cell- 
walls,  which  formerly  contained  protoplasm  and  nuclei. 

69.  The  mucilaginous  part  of  slippery-elm  bark  belongs 
to  the  inner  bark  outside  the  cambium  (top  of  p.  71). 

70.  See  note  on  cells  in  §  68  above. 

73.  Leaf  epidermis.  —  The  purple  leaves  of  the  plant 
known  in  greenhouses  as  Tradescantia  are  excellent  and 
may  supplement  material  from  bean  leaves. 


INTROtotTCTiON   TO  PLANT  BIOLOGY  27 

75.  Bean  flowers.  —  Eight  or  ten  weeks  before  this 
lesson,  plant  seeds  of  extra-early  beans  (e.g.,  Early  Valen- 
tine or  Early  Six- Weeks).  In  the  early  autumn,  bean 
plants  with  belated  flowers  may  usually  be  found  in 
gardens.  When  grown  in  schoolrooms  in  pots  and 
window-boxes,  the  plants  often  flower.  Pods  ("  string 
beans")  may  be  purchased  at  markets,  or  kept  preserved 
in  two  to  five  per  cent  formalin  solution. 

Ovules  and  ova.  —  Avoid  confusing  plant  ovule  (p.  78) 
and  animal  ovum  (egg-cell),  for  within  the  ovule  is  the 
plant  egg-cell. 

Similarly,  pollen-grains  do  not  correspond  to  sperm- 
cells  of  animals  and  cryptogamic  plants.  A  correct  com- 
parison in  popular  form  is  the  statement  that  some  pro- 
toplasm inside  the  pollen-grain  becomes  a  fertilizing  cell 
equivalent  to  a  sperm-cell  of  an  animal  or  lower  plant. 

Many  teachers,  some  elementary  books,  and  a  well- 
known  book  on  heredity  confuse  the  animal  and  plant 
reproductive  cells  in  the  way  stated  above. 

77.  Dorsal  and  ventral.  —  The  statement  that  the  con- 
cave edge  of  the  pod  is  called  ventral  because  down  may 
prove  misleading  in  that  it  may  suggest  that  ventral  and 
lower,  dorsal  and  upper,  are  always  synonymous.     There 
are  some  exceptions  that  should  be  mentioned.     For  ex- 
ample, some  animals  lie  constantly  on  their  sides  ("flat 
fishes,"  or  flounders)  and  hence  ventral  is  not  "down," 
but  it  is  determined  by  comparing  the  position  of  the 
organs    (especially    the    backbone)    with    typical    fishes. 
Likewise,  the  lower  surfaces  of  some  parts  of  plants  show 
by  their  structure  and  development  that  they  correspond 
with  the  dorsal  side  of  typical  cases,  and  hence  lower  in 
such  cases  is  dorsal. 

78.  Bean  seeds.  —  Materials  :  lima  beans,  scarlet  runner, 
white  Dutch  runner,  yellow  six-weeks,  golden-eyed  wax, 
Windsor  beans  (Vicia).     The  runner  beans  named  above 


28  TEACHER^   MANUAL   OF  BIOLOGY 

are  not  as  likely  to  decay  during  germination  as  are 
limas. 

Details  of  structure.  —  In  the  study  of  the  bean  seed, 
such  details  as  chalaza  and  raphe  are  best  omitted.  They 
mean  little  except  in  comparison  with  embryonic  stages 
that  beginning  students  cannot  possibly  know  or  under- 
stand. 

References  for  teachers :  Lloyd,  1904,  p.  146 ;  Ganong, 
1899,  pp.  161-166.  Also  see  §§  135-145  in  this  Manual. 

Reference  for  students :  Atkinson's  First  Studies  of 
Plant  Life,  and  his  Botany  for  Schools.  Also  the  various 
Bergen  botanies. 

79.  Bean  markings.  —  The  heart-shaped  and  trans- 
lucent marking  seen  in  green  beans  on  the  side  of  the 
hilum  opposite  the  micropyle  is  at  one  end  of  a  ridge 
(raphe),  which  is  formed  from  the  stalk  of  the  ovule. 
At  the  other  end  of  the  raphe  is  the  chalaza.  The  heart- 
shaped  marking  has  been  called  strophiole.  Of  course, 
these  details  are  not  for  beginners  in  biology. 

81.  Germination  as  applied  to  awakening  of  seeds  has 
been  in  use  so  long  that  it  seems  absurd  to  insist  in  ele- 
mentary courses  upon  the  strict  technical  meaning  as 
does  Coulter  in  Plant  Structures,  pages  187  and  214. 
There  seems  to  be  no  possible  confusion  of  the  phrases 
" germination  of  spores"  and  " germination  of  seeds." 
At  any  rate,  the  long-established  popular  usage  of  the 
word  "germination"  cannot  be  changed  by  any  attempt 
of  biologists  who  prefer  lo  limit  it  to  a  technical  meaning 
in  connection  with  spores. 

Another  method  for  germinating  seeds  (p.  85  in  Applied 
Biology).  —  Line  a  glass  tumbler,  or  a  cylindrical  lamp- 
chimney,  with  blotting-paper  (preferably  dark  colored)  ; 
fill  the  center  with  moist  sphagnum,  sawdust,  soft  paper, 
or  cotton;  push  seeds  down  between  the  glass  and  the 
blotting-paper ;  keep  moist  and  warm ;  shade  with  a 


INTRODUCTION  TO  PLANT  BIOLOGY  29 

sheet  of  paper  held  around  the  glass  by  means  of  a  rubber 
band.  A  modification  of  the  same  method  is  as  follows : 
Select  two  sheets  of  glass  of  equal  size.  Lay  one  on  the 
table;  on  it  place  a  layer  of  cotton  or  several  layers  of 
soft  papers,  then  a  sheet  of  dark-colored  blotting-paper; 
on  this  arrange  the  seeds  about  two  inches  from  one 
edge  of  the  glass ;  then  cover  with  the  other  glass ;  and 
finally  tie  the  two  glasses  together  or  hold  with  strong  rub- 
ber bands.  Keep  moist,  and  shade  with  a  sheet  of  paper. 

The  growth  of  molds  in  sawdust  (p.  85  in  Applied  Biology) 
often  interferes  with  the  germination  of  seeds;  but  this 
may  be  prevented  by  steaming  the  sawdust  in  a  sterilizer 
or  by  boiling  it  in  water  and  then  allowing  it  to  drain. 

82-86.  Soil.  —  References :  Farmers'  Bulletin  408; 
Goodrich's  First  Book  of  Farming;  Burkett,  Stevens  and 
Hill's  Agriculture  for  Beginners. 

82-122.  Plant  physiology.  —  Many  excellent  experi- 
ments are  described  in  Farmers'  Bulletin  408.  Osterhout's 
Experiments  with  Plants  is  very  useful.  Atkinson's  books, 
especially  First  Studies  of  Plant  Life,  and  Botany  for 
Schools,  Ganong's  Teaching  Botanist  and  his  Laboratory 
Course  in  Plant  Physiology  will  suggest  new  ways  and 
additional  experiments. 

84,  85.  Conserving  water  in  soil.  See  Farmers'  Bulletin 
266  and  Yearbook  Reprint  495,  1908,  on  "Soil  Mulches  for 
Checking  Evaporation." 

88.  Osmosis.  —  Many  teachers  demonstrate  osmosis  by 
means  of  hen's  egg  arranged  as  follows :  Select  an  egg 
several  weeks  old  in  which  the  air  space  at  the  larger  end 
has  been  enlarged  by  evaporation  of  water  (space  may  be 
seen  when  holding  egg  before  a  lamp).  Carefully  chip  a 
small  hole  so  as  not  to  puncture  the  shell-membrane,  or 
stand  the  egg  on  its  larger  end  in  a  small  dish  containing 
an  inch  of  vinegar  until  mineral  matter  of  shell  is  dis- 
solved at  this  end.  Now  punch  a  hole  in  shell  and  mem- 


30  TEACHERS'  MANUAL  OF  BIOLOGY 

brane  at  the  small  end  of  the  egg,  insert  a  small  glass 
tube  12  to  20  inches  long,  and  pour  melted  paraffine  or 
sealing  wax  around  the  tube  so  as  to  seal  to  the  shell. 
Now  stand  egg  in  a  tumbler  with  water  about  one  inch 
deep  and  osmosis  will  begin  if  the  membrane  at  the  larger 
end  has  not  been  punctured. 

The  experiment  suggested  in  §  88  of  the  Applied  Biology 
may  be  reversed  as  follows  and  will  eradicate  all  notions 
on  the  part  of  students  that  gravitation  is  somehow  in- 
volved in  osmosis.  If  we  should  fill  the  diffusion-shell 
and  the  glass  tube  with  water  and  place  the  shell  in 
molasses  at  the  beginning  of  the  experiment,  the  water 
will  osmose  out  of  the  shell  more  rapidly  than  the  mo- 
lasses osmoses  into  the  shell,  and  the  column  of  water 
will  slowly  descend. 

Note  in  the  experiment  in  §  88  that  as  the  molasses 
slowly  osmoses  out  into  the  water,  the  water  also  becomes 
a  solution  of  sugar;  and  as  the  water  becomes  heavier 
with  molasses  in  solution,  it  osmoses  into  the  molasses  in 
the  shell  more  slowly.  This  will  continue  until  a  given 
quantity  of  the  mixed  liquid  outside  the  diffusion-shell, 
compared  with  the  same  amount  of  fluid  from  within  the 
shell,  will  be  found  to  have  equal  quantities  of  molasses 
and  water.  In  other  words,  water  will  osmose  into  the 
molasses  and  molasses  into  the  water  until  an  equilibrium 
is  established. 

Preserving  membranes.  —  Adding  some  formalin,  boric 
acid,  menthol,  or  thymol  to  the  water  will  prevent  fer- 
mentation and  injury  to  the  membrane  by  bacteria.  As 
soon  as  the  experiment  is  completed,  wash  the  membrane, 
and  either  insufflate  so  as  to  dry  quickly,  or  preserve  in  a 
fruit-jar  with  a  weak  solution  of  formalin  or  other  anti- 
septic. 

Popular  expressions.  —  The  word  "attracts"  as  a  short 
description  of  osmotic  phenomena  (pp.  90,  92  in  Applied 


INTRODUCTION   TO  PLANT  BIOLOGY  31 

Biology)  is  criticized  by  some  physicists.  Molecular  ex- 
planation may  be  given  to  students  who  have  had  physics, 
but  others  must  be  content  with  observing  the  fact  that 
the  water  osmoses  into  the  molasses  faster  than  the  mo- 
lasses into  the  water.  This  statement  will  avoid  the  word 
" attracts,"  which,  like  ''suction"  for  air-pressure  in  pumps, 
may  mislead  as  an  apparent  attempt  at  explaining  rather 
than  at  describing  a  phenomenon.  However,  there  appears 
to  be  no  more  reasonable  objection  to  the  use  of  "attracts" 
and  "suction"  for  the  sake  of  brevity  than  there  is  to  saying 
that  the  "sun  rises,"  the  "wind  blows,"  and  many  similar 
phrases.  Such  time-honored  popular  expressions  are  ex- 
ceedingly useful,  and  they  certainly  do  not  mislead  any 
one  who  studies  science,  which  explains  such  natural  phe- 
nomena. 

Diffusion-shells,  \  X  3  inches,  cost  about  15  cents  each 
and  $1.50  per  dozen.  Goldbeater's  bags,  10  to  12  cents 
each,  $1  to  $1.25  per  dozen.  Eimer  and  Amend,  New 
York.  In  order  to  help  teachers  who  wish  only  one  or  two 
shells  or  bags,  the  author  of  this  "Manual"  will  mail  them 
at  cost  to  any  one  who  sends  a  stamped  and  self -addressed 
envelope  and  postage  stamps  in  payment. 

Parchment  paper  tubing  may  be  purchased  for  about 
10  cents  per  foot.  A  piece  3  inches  long  may  be  soaked 
in  water,  folded,  and  tied  at  one  end  so  as  to  form  a  water- 
tight cup.  See  Ganong,  1910,  pp.  344-348.  See  also 
§  398  in  this  Manual 

Exosmosis.  —  If  students  are  confused  by  the  fact  that 
sugar  osmoses  out  into  the  water,  which  does  not  happen 
with  living  root  cells,  perform  an  experiment  with  a  semi- 
permeable  membrane,  which  prevents  sugar  from  osmosing 
outward.  See  Ganong,  1910,  p.  347. 

91.  "  Suction."  —  The  teacher  should  make  sure  that  the 
students  understand  that  atmospheric  pressure  is  responsi- 
ble for  the  "lifting  power  of  transpiration."  Thus  under- 


32  TEACHERS'   MANUAL   OF  BIOLOGY 

stood,  there  seems  to  be  no  reasonable  objection  to  the 
word  " suction"  as  popularly  applied  to  pumps.  See  note 
on  "popular  expressions"  in  §  88  in  this  Manual. 

92.  Ascending  current.  —  For  demonstrating  the  rise  of 
colored  fluid  in  stems,  catnip  twigs  are  excellent,  and  may 
be  obtained  late  in  the  autumn  after  many  other  plants  are 
frosted. 

93.  Transpiration.  —  The  word  "evaporation"  has  been 
used  freely  because  it  requires  no  definition.     Transpira- 
tion is  now  known  to  be  evaporation.     The  word  "trans- 
piration," meaning  breathing  or  exhaling,  is  obviously  an 
heirloom  from  the  old-time  botanists,  who  seem  to  have 
considered  transpiration  of  water  as  part  of  a  breathing 
process  similar  to  that  of  animal  lungs,  because  in  both 
watery  vapor  is  given  off.     However,  it  is  best  that  be- 
ginners should  not  know  the  etymological  derivation  of  the 
word  "transpiration,"  for  it  suggests  connection  with  the 
true  respiration  process.     Similarly,  it  will  later  be  pointed 
out  that  in  animal  physiology  there  is  a  decided  gain  in 
clearness  by  considering  the  oxygen-supply  and  the  excre- 
tory phases  of  respiration  as  essentially  independent  and 
merely  associated  in  the  same  organs.     After  the  students 
understand  the  method  by  which  water  is  lost  from  the 
leaves,  it  is  well  that  they  should  learn  "transpiration" 
as  a  single  word  meaning  "evaporation  of  water  from 
plant  leaves."    To  reverse  this  order  of   really  getting 
the  idea  before  the  word  is  to  encourage  the  all  too  com- 
mon practice  of  using  scientific  terms  without  teaching 
the  ideas  for  which  the  words  should  stand. 

Reference  :  Concerning  transpiration,  see  Ganong,  1910, 
pp.  331-335;  and  especially  in  connection  with  the  ex- 
periment on  page  96  of  the  Applied  Biology. 

97.  Plant  foods.  —  In  popular  usage,  "fertilizers"  are 
known  as  "plant  foods";  but  some  botanists  object  to 
this,  reserving  the  word  "food"  for  carbohydrates,  fats, 


INTRODUCTION   TO  PLANT  BIOLOGY  33 

etc.  "Raw  plant  food"  seems  still  more  misleading  as 
applied  to  nitrates,  carbon  dioxide,  etc.  Lacking  an 
authoritative  term,  the  phrase  "plant  food-materials"  has 
been  used  in  the  Applied  Biology  for  the  simple  compounds 
required  by  green  plants. 

98.  Elements  in  carbohydrates.  —  Strictly  speaking,   a 
carbohydrate  is  composed  of   C  and  the  hydroxyl  OH, 
which  latter  is  derived  from  water  absorbed  by  plants 
(p.    100   in  the  Applied  Biology).     Students  who  have 
studied   little   chemistry  should   be   instructed  that  for 
carbohydrate-making    the    plant    gets    three    elements, 
namely,  carbon  from  carbon  dioxide  and  hydrogen  and 
oxygen  from  water,  and  that  the  oxygen  of  the  carbon 
dioxide  is  not  built  into  the  sugar  or  the  starch  that  is  made. 

At  the  top  of  page  100  in  the  Applied  Biology  change 
"most"  to  "numerous"  so  as  to  read :  "Numerous  plants 
without  chlorophyll  are  saprophytes." 

99.  Saprophytes.  —  Insert    the    word    "non-parasitic" 
before  "plants"  in  the  last  clause  of  the  first  paragraph, 
so  as  to  make  it  mean  that  non-parasitic  plants  without 
chlorophyll  absorb  food  from  decaying  organisms. 

Carbon  dioxide  taken  from  the  air  and  used  in  making 
starch  may  be  demonstrated  as  stated  by  Ganong,  1910, 
pp.  301-303.  A  square  meter  of  leaf  surface  absorbs 
from  air  J  of  a  liter  of  pure  carbon  dioxide  per  hour  in 
bright  daylight,  and  gives  off  almost  the  same  amount  of 
oxygen. 

100.  Photosynthesis.  —  Many  teachers  speak  of  "starch- 
making"  as  if  synonymous  with  photosynthesis,  but  that 
is  probably  in  large  part    sugar-making.     Hence  it    is 
"carbohydrate-making."     Photosynthesis     involves     the 
idea  of  carbohydrate  synthesis  by  the  action  of  light  on 
chlorophyll-containing  cells.     There  is  no  good  substitute 
for  the  word.     The  process  is  of  such  great  significance 
that  the  term  deserves  memorizing. 


34  TEACHERS'  MANUAL  OF  IHOLOGY 

S  H  gar  is  probably  first  formed  in  photosynthesis  and 
then  converted  by  enzyme  action  into  starch;  but  only 
experiments  dealing  with  the  starch  in  leaves  arc  prac- 
ticable in  elementary  studies. 

Starch  in  leaves.  —  Some  kinds  of  leaves  (e.g.,  nas- 
turtium) require  about  forty-eight  hours  in  darkness 
before  the  starch  entirely  disappears. 

It  has  been  shown  that  direct  sunlight  gives  more 
light  than  leaves  can  use  in  photosynthesis  (bottom  of 
p.  103  in  the  Applied  Biology). 

Starch-test.  —  While  starch  is  the  only  common  sub- 
stance in  plants  that  gives  the  deep  blue  color  with  iodine, 
there  are  other  substances  that  give  some  lighter  shades 
of  blue  (e.g.,  put  a  drop  of  iodine  solution  on  filter-paper 
or  cotton  and  the  cellulose  is  often  colored  light  blue, 
especially  if  there  is  acid  present).  In  all  doubtful  cases, 
chemists  use  special  tests  in  addition  to  the  iodine  test. 

Starch  in  leaves.  —  The  directions  for  covering  part  of 
a  leaf  with  cork  or  tin-foil,  Applied  Biology  (p.  103),  should 
have  cautioned  against  fitting  either  of  these  substances 
tightly  on  the  lower  surface  of  a  leaf,  for  the  free  entrance 
of  carbon  dioxide  may  be  prevented  thereby.  A  partial 
control  experiment  may  be  made  by  pinning  corks  only 
on  the  lower  sides  of  some  leaves,  and  comparing  these 
with  leaves  covered  on  both  sides.  The  absence  of 
starch  from  the  leaves  with  corks  on  lower  sides  suggests 
that  carbon  dioxide  has  been  kept  out  of  the  stomata. 
See  Ganong  in  School  Science  and  Mathematics,  Vol.  6, 
p.  298,  April,  1906.  Also  his  Plant  Physiology,  second 
edition,  p.  90 ;  and  his  Teaching  Botanist,  1910,  pp.  294-297. 

101.  Starch  disappears  from  leaves  in  light  as  well  as 
in  darkness ;  but  this  is  not  easily  proved,  because  starch 
is  formed  more  rapidly  than  it  can  be  removed  from 
leaves.  See  reference  to  digestion  in  §  102  in  the  Applied 
Biology. 


INTRODUCTION  TO  PLANT  BIOLOGY 


35 


105.  Oxygen    from    plants.  —  In    demonstrating    the 
liberation  of  oxygen  from  Elodea,  Cabomba,  Spirogyra  or 
other  water  weed  (p.  112),  keep  the  funnel  several  inches 
from  the  bottom  of  the  battery-jar  in  order  to  allow  the 
entrance  of  more  carbon  dioxide.     Select  a  large  battery- 
jar  or  aquarium,  which  exposes  a  large  surface  of  water 
to   the   air.     Actively  growing   plants   in   warm,    sunny 
weather  give  best  results.     Land  plants,  sometimes  sug- 
gested for  a  similar  experiment,  are  useless  (Ganong,  1910, 
pp.  238,  239,  308,  Fig.  23;    also  in  School  Science  and 
Mathematics,  Vol.  6,  1906,  p.  297). 

See  note  in  §  100  of  this  Manual. 

106.  Method  for  demonstrating  C02  excretion.  —  A  rep- 
resents a  pan  or  dish  partly  filled  with  water.     C  is  a 
wooden  block  or  other 

support  for  saucer  B, 
which  holds  lime-  or 
barium-water.  D  is 
the  position  of  a  green 

leaf  Which  maybe  laid  AppARATUS  FOR  DEMONSTRATING  EXCRE- 
across  top  of  dish  B.  TION  OF  CARBON  DIOXIDE.  (See  Text, 

E  is  an  inverted  bat-      §  106-> 

tery-jar  or  crystallizing  dish.  It  is  well  to  draw  out 
some  water  from  inside  E  by  means  of  a  rubber  tube.  A 
film  of  calcium  (or  barium)  carbonate  forms  in  B.  A 
parallel  control  experiment  should  omit  the  leaf.  Of 
course,  light  should  be  excluded;  but  a  parallel  control 
kept  for  the  same  hours  in  light  is  important.  (Jean 
Broadhurst,  in  Torreya,  Dec.,  1911,  p.  261.) 


CHAPTERS  VI  AND  VII 

COMPARISON  AND  CLASSIFICATION  OF  ANIMALS  AND 
PLANTS 

114.  Metabolism.  —  Substitute  the  word  "nutrition" 
for  ''metabolism"  in  third  line  from  bottom  of  page  125 
in  the  Applied  Biology. 

At  the  top  of  page  126  in  the  Applied  Biology  is  the 
sentence  "This  is  constructive  metabolism."  Some  bota- 
nists hold  that  synthesis  of  foods  (starch,  fats,  etc.)  in 
plants  is  better  not  included  in  constructive  metabolism, 
but  limit  that  term  to  formation  of  new  protoplasm. 

122.   See  note  on  §  75  in  this  Manual. 

127.  Phylum  Chordata,  instead  of  Vertebrata,  is  now 
approved  by  many  zoologists ;  but  see  §  343  in  the  Applied 
Biology  and  in  this  Manual. 

122.  Sperm-cell   and   pollen-grain.  —  On   the    common 
confusion  of  animal  sperm-cell  with  plant  pollen-grain, 
see  §  75  in  this  Manual. 

123.  Linnceus.  —  The  statement  that  he  "introduced" 
binomial    nomenclature   might    be    interpreted    as    "in- 
vented "  ;  but  the  idea  of  a  double  name  for  animals  and 
plants  antedates  the  work  of  the  famous  botanist.     The 
fact  is  that  his  writings  brought  it  into  universal  use 
among  biologists. 

129.  Homology.  —  The  word  "homologies"  for  struc- 
tural resemblances  might  be  introduced  in  this  section 
of  the  Applied  Biology,  but  it  has  no  particular  advantage 
at  this  early  stage.  The  abstract  idea  of  "homology" 
certainly  does  not  belong  here. 

132.  Plant  names.  —  In  Part  II  there  are  few  scientific 

36 


CLASSIFICATION  OF  ANIMALS  AND  PLANTS      37 

names  of  plants,  but  it  is  suggested  that  teachers  supple- 
ment the  book  by  mentioning  important  generic  and  some- 
times also  specific  names  of  familiar  plants.  This  is 
better  than  loading  the  text  with  such  names,  for  they 
certainly  tend  to  give  some  young  readers  the  impression 
that  biology  is  difficult. 

133.  Classification.  —  Some  authors  prefer  the  word 
" sub-kingdom "  instead  of  the  words  " phylum"  (for 
animals)  and  " division"  (for  plants). 

There  are  authorities  who  would  add  bacteria  and 
slime-molds  (Myxomycetes)  as  sub-divisions  3  and  4 
under  Thallophyta  (p.  144  in  Applied  Biology). 

The  division  of  Thallophytes  into  Algae  and  Fungi  is 
a  physiological  rather  than  a  true  taxonomic  arrangement, 
but  is  still  the  best  for  elementary  study  and  does  not  in 
the  least  interfere  with  advanced  systematic  studies. 

It  should  also  be  noted  that  the  slime-molds  (Myxo- 
mycetes or  Mycetozoa)  are,  by  some  authors,  regarded  as 
animals,  not  plants.  (See  " Mycetozoa"  in  new  Ency- 
clopaedia Britannica,  1911.) 

Number  of  known  species  of  animals.  —  It  should  interest 
students  to  know  that  there  are  many  recently  discovered 
species  of  animals.  In  the  following  list  the  figures  in 
parentheses  are  the  estimates  of  number  of  species  known 
twenty-five  years  ago,  while  the  larger  figures  are  1911 
estimates  (Science,  Vol.  35,  p.  468,  March  22,  1912.) 

Insects,  360,000  (200,000).  Protozoa,  8000  (4130). 
"Worms,"  about  14,000  (6300).  Sponges,  2500  (600). 
Ccelenterates,  4500  (3000).  Echinoderms,  4000  (2370). 
Myriapods,  2000  (800).  Arachnids,  16,000  (4000). 
Crustaceans,  16,000  (5600).  Mollusks,  61,000  (21,320). 
Fishes,  13,000  (9000).  Amphibians,  1400  (1000).  Rep- 
tiles, 3500  (2500).  Birds,  13,000  (10,000).  Mammals, 
3500  (2300).  These  and  smaller  groups  bring  the  totals 
up  to  522,400  in  1911 ;  273,220  in  1886. 


CHAPTER  VIII 
SEED-PLANTS 

134.  Order  of  study.  —  In  addition  to  variation  in 
order  of  study  of  chapters  in  the  Applied  Biology  as  sug- 
gested in  §§  32  and  65  in  this  Manual,  it  would  be  easy 
to  start  with  this  Chapter  VIII  and  give  the  usual  kind 
of  botany  course  with  comparison  of  seeds,  roots,  etc., 
from  the  very  beginning.  If  that  plan  is  preferred  for 
plant  study  as  a  part  of  biology,  or  for  a  short  course  in 
botany,  assign  the  sections  of  the  Applied  Biology  as 
follows :  Begin  with  bean  seed  (§§  78,  79) ;  then  study  the 
bean  pod  (§  77)  enough  to  show  its  relation  to  the  seeds ; 
then  §§  80,  81;  then  other  seeds  (§§  135-145).  Next 
study  roots  (§§  67,  68,  146-155).  Then  stems  (§§  69, 
70,  156-181).  Next  leaves  (§§  72,  73,  181-188).  Then 
flowers  (§§  74,  75,  189-211,  possibly  omitting  §§  209-211). 
Finally,  in  the  studies  of  seed-plants  take  up  fruits  (§§  76, 
77,  212-218).  A  series  of  studies  of  plant  physiology 
(§§  82-110)  may  come  at  this  stage ;  or  those  studies  may 
be  broken  up  and  functions  of  roots,  stems,  leaves,  and 
flowers  included  in  connection  with  lessons  on  these 
topics  taken  from  sections  suggested  above.  For  example, 
§§  82-90  with  roots;  91-98  with  stems;  99-106  after 
leaves. 

Studies  of  spore-plants,  selected  from  Chapter  IX, 
may  close  such  a  specially  arranged  course  in  botany. 

The  above  suggestion  in  regard  to  starting  with  Chapter 
VIII  is  another  possible  variation  in  the  use  of  the  Applied 
Biology,  but  the  authors  of  that  book  would  prefer  a  short 

38 


SEED-PLANTS  39 

course  in  botany  consisting  of  Chapters  I,  II,  III,  V,  VII, 
VIII,  and  IX,  and  in  this  order.  This  might  be  shortened 
by  omitting  the  animal  part  or  even  all  of  Chapter 
III ;  by  selecting  the  essentials  of  plant  physiology  in 
Chapter  V  (this  will  be  done  in  the  briefer  book,  Intro- 
duction to  Biology) ;  and  perhaps  by  omitting  Chapter  VII. 

134-264.  From  higher  to  lower  plants  is* the  order  pre- 
ferred by  the  authors  of  the  Applied  Biology,  However, 
great  modification  of  this  order,  even  complete  reversal 
so  that  one-celled  plants  are  studied  first,  might  be  very 
successful  in  the  hands  of  expert  teachers  of  botany. 
Such  an  order  has  been  used  for  animals  in  Part  III  of  the 
Applied  Biology.  But  in  all  cases  a  many-celled  type 
should  be  used  in  Part  I  as  an  introduction. 

134.  Emphasis  on  seed-plants.  —  Many  botanists  whose 
own  researches  are  chiefly  connected  with  the  crypto- 
gamic  plants  are  fond  of  criticizing  those  elementary  text- 
books of  botany  that  give  most  of  their  prominent  space 
to  studies  of  seed-plants.  There  is  some  justification  for 
this  point  of  view  in  the  pure  science  of  botany;  but  it 
cannot  be  denied  that  in  our  practical  life  the  seed-plants 
are  vastly  more  important  than  the  lower  forms.  Hence 
botany  taught  as  a  part  of  general  education  may  properly 
give  very  much  attention  to  the  seed-plants.  Certainly 
in  a  course  of  applied  biology  the  higher  plants  deserve 
great  prominence.  The  plain  truth  is  that  many  of  the 
facts  and  theories  that  make  study  of  cryptogamic  botany 
so  fascinating  to  advanced  students  are  far  from  being 
illuminating  to  those  who  are  making  a  beginning  in  the 
study  of  plant  life.  (See  Lloyd,  1904,  p.  119;  Ganong, 
1899,  p.  34.) 

In  the  chapter  on  seed-plants  in  the  Applied  Biology  the 
authors  have  included  those  facts  of  structure,  function, 
and  development  that  have  been  pronounced  most  in- 
teresting and  most  useful  by  numerous  intelligent  citizens 


40  TEACHERS'   MANUAL   OF  BIOLOGY 

who  have  only  general  information  concerning  plants. 
Such  a  basis  of  selection  has  undoubtedly  caused  neglect 
of  certain  topics  that  many  professional  botanists  would 
emphasize,  and  the  insertion  of  some  material  that  has  no 
direct  bearing  on  the  pure  science  of  botany.  All  this  is 
the  result  of  trying  to  find  that  botanical  study  of  the  seed- 
plants  which  may  have  practical,  intellectual,  and  aesthetic 
application  in  the  daily  life  of  average  intelligent  citizens. 
(See  discussion  of  "botany  for  the  masses"  by  Lloyd, 
1904,  p.  88.) 

Since  the  study  of  the  bean  plant  (or  some  other  avail- 
able one)  has  given  general  knowledge  concerning  a  seed- 
plant,  it  seems  best  that  this  chapter  should  deal  with 
the  most  interesting  and  most  useful  adaptations  of  com- 
mon seed-plants.  For  elementary  lessons,  and  for  all 
practical  purposes  outside  of  technical  discussions  in 
advanced  botany,  there  appears  to  be  no  more  convenient 
arrangement  of  studies  of  seed-plants  than  the  familiar 
one  of  seed,  root,  stem,  leaf,  flower,  and  fruit.  For 
teaching  purposes  this  presents  plants  as  beginners  actually 
see  them  and,  as  a  practical  matter,  the  teacher  can  not 
do  better  in  a  first  short  course  than  to  treat  seed-plants  as 
composed  of  several  definite  units,  organs,  or  elements 
(root,  stem,  leaf,  flower)  capable  of  some  adaptive  modi- 
fication within  limits.  Such  an  interpretation  inevitably 
arouses  the  interest  of  the  beginner,  whose  studies  are 
necessarily  comparatively  anatomical  at  basis. 

It  is  true  that  such  a  division  of  seed-plant  studies  is 
in  danger  of  drifting  far  toward  an  out-of-date,  formal- 
istic  conception  (see  Ganong,  1899,  p.  144) ;  but  there 
will  be  a  minimum  of  such  danger  and  a  decided  gain  in 
efficiency  of  the  teaching  if  to  the  old  botanical  trinity 
of  root,  stem,  and  leaf  considered  as  established  organs 
or  units  from  which  all  other  parts  came  through  modi- 
fication, there  be  added  buds,  flowers,  fruits,  and  seeds,  as 


SEED-PLANTS  41 

topics  for  comparative  studies.  And  within  this  series  of 
topics  it  will  be  helpful  to  point  out  similarities,  taking 
care  that  in  doubtful  cases  similarities  are  not  understood 
as  proving  origins  ;  e.g.,  leaf -like  stamens  do  not  prove  that 
stamens  are  modified  leaves  (see  §  185). 

135-145.  Seeds.  —  References  for  students  :  Atkinson's 
First  Studies,  and  his  Botany  (1910),  Chap.  I;  Andrew's 
Practical  Botany;  Bergen's  Essentials  and  Foundations; 
Bergen  and  Caldwell's  Practical  Botany  (1911). 

For  teachers:  Ganong  (1899  or  1910),  Part  II;  Lloyd 
(1904),  pp.  146-153.  " Testing  Seeds"  (Farmers'  Bul- 
letin 428). 

135-217.  Seed-plants.  —  These  sections  in  the  Applied 
Biology  direct  the  comparative  study  of  seed-plants  along 
such  familiar  lines  that  few  specific  references  seem  needed 
in  this  Manual.  The  same  topics  (root,  stem,  leaf,  etc.) 
occur  in  many  well-known  text-books  of  botany  to  which 
teachers  and  students  are  likely  to  refer. 

References :  The  authors  of  the  Applied  Biology  would 
commend  the  books  of  botany  for  high  schools  by  Atkin- 
son, Bergen,  Bergen  and  Caldwell,  Bailey,  Stevens, 
Andrews,  Coulter,  Leavitt  (revised  Gray),  Osterhout, 
Clute,  Bessey,  Barnes  for  reference  or  supplementary 
work  on  most  points  mentioned  in  Chapter  VIII  of  the 
Applied  Biology.  (See  selected  list  in  Appendix  III  of 
this  Manual.) 

An  up-to-date  list  of  advanced  books  of  botany  for 
teachers  is  given  by  Ganong,  1910,  pp.  176-226  —  a 
chapter  that  every  teacher  of  biology  should  read. 

137.  Squash  seeds.  —  Most  varieties  of  squashes  and 
pumpkins  have  seeds  too  small  to  be  convenient  for 
study,  and  seedsmen  should  be  asked  to  send  seeds  of 
the  Hubbard  varieties  or  of  others  equally  large. 

There  is  no  accurate  botanical  distinction  between  the 
words  "squash"  and  " pumpkin";  e.g.,  the  Connecticut 


42  TEACHERS'  MANUAL  OF  BIOLOGY 

field  or  "  Yankee"  pumpkin,  the  yellow  crookneck  squash, 
the  scallop  squash,  and  many  gourds  are  varieties  of 
Curcubita  Pepo,  while  the  Hubbard  and  the  mammoth 
squashes  (also  commonly  called  pumpkins)  belong  to  C. 
maxima. 

138.  Castor-oil  seed.  —  It  does  not  seem  desirable  to 
confuse  elementary  study  with  the  details  of  such  markings 
as  raphe,  chalaza,  etc.,  because  they  are  of  no  particular 
significance  to  a  beginner.  In  order  to  answer  possible 
questions,  the  teacher  may  need  to  know  some  of  the 
details  mentioned  by  Lloyd,  1904,  p.  151.  The  essential 
points  are  as  follows :  The  micropyle  is  surrounded  by  a 
spongy  mass  (caruncle)  of  unknown  function,  but  possibly 
for  absorbing  water  when  germination  begins.  This 
spongy  mass  is  somewhat  nearer  the  side  of  the  seed  on 
which  is  a  longitudinal  ridge  (raphe).  At  one  end  of  this 
ridge  (toward  the  micropyle)  is  the  hilum  (best  seen  in 
seeds  in  a  mature  fruit  of  the  castor-oil  plant),  and  at  the 
other  end  of  the  ridge  is  the  chalaza.  After  removing  the 
seed-coat,  a  reddish-colored  spot  will  be  seen  beneath  the 
chalaza,  and  from  it  delicate  veins  radiate.  These  veins 
carried  food  during  the  development  of  the  seed. 

Supplementary  facts.  —  The  authors  of  the  Applied 
Biology  have  long  believed  that  it  is  well  worth  while  to 
make  occasional  digression  and  give  students  supple- 
mentary information.  Here  is  such  an  opportunity: 
The  name  "castor-oil  plant"  refers  to  the  oil  obtained 
by  pressing  the  seeds  and  used  in  medicine  and  for  lu- 
bricating machinery.  The  word  "castor"  probably  refers 
to  odor  of  the  plants,  which  resembles  that  of  beavers 
that  belong  to  the  genus  Castor.  The  botanical  name  for 
the  plant  is  Ricinus,  from  Latin  meaning  a  tick ;  and  was 
probably  given  because  the  seeds  resemble  wood-ticks  or 
sheep-ticks.  The  seeds  contain  a  powerful  poison  known 
as  ricin. 


SEED-PLANTS  43 

It  is  true  that  such  facts  are  not  necessary  for  technical 
botany ;  but  teachers  of  science  in  high  schools  should  not 
be  overanxious  concerning  the  aims  and  needs  of  technical 
science  in  colleges.  The  fact  is  that  the  questions  of 
students  indicate  that  they  are  interested  in  points  that 
are  of  human  interest  apart  from  their  scientific  connections. 
Also,  occasional  reference  to  the  language  derivation 
will  add  interest  to  the  study  both  of  science  and  of 
language.  Teachers  of  science  should  occasionally  take 
such  opportunities  for  giving  a  glimpse  of  the  origin  of 
some  scientific  names,  for  the  sake  of  broadening  interest 
in  language  study  and  its  applications. 

139.  Corn  grain.  —  While,  strictly  speaking,  this  is 
a  fruit  corresponding  to  a  bean  pod  with  one  seed, 
beginners  will  use  the  word  "seed"  in  the  popular  sense; 
and  "seed  corn"  will  continue  to  be  sold  and  planted 
in  spite  of  criticism  by  botanists.  The  exact  meaning  of 
a  seed  cannot  be  clear  until  after  the  study  of  fruits 
(§§  212-218).  The  term  "testa"  is  not  properly  appli- 
cable to  the  com  grain,  because  its  "hull"  is  a  testa 
consolidated  with  the  wall  of  the  ovary.  In  fact,  the 
hull  is  like  an  imaginary  bean  pod  with  one  seed  whose 
coat  is  consolidated  with  the  pod.  The  sunflower  fruit 
(commonly  called  "seed")  has  its  testa  and  ovary  wall 
separate. 

The  shield-like  body  (scutellum)  embedded  hi  the  corn 
grain  is  probably  (not  certainly)  a  cotyledon. 

References  for  teachers:  Lloyd,  1904,  pp.  149-150; 
Ganong,  1899,  p.  169,  or  1910. 

References  for  students:  "School  Lessons  on  Corn" 
(Farmers'  Bulletin  409);  "Germination  of  Seed  Corn" 
(Farmers'  Bulletin  253} ;  "Seed  Corn"  (Farmers'  Bulletin 
415).  Also  text-books  mentioned  in  §  135  in  this  Manual. 

143,  144.  Epicotyl  and  hypocotyl  are  just  as  easily 
learned  as  caulicle  or  radicle  of  the  older  botanists.  The 


44  TEACHERS'   MANUAL   OF  BIOLOGY 

word  plumule  for  the  bud  on  the  epicotyl  is  still  useful 
at  times.  Some  authors  use  hypocotyl,  but  retain  plumule 
instead  of  epicotyl. 

145.  Physiology  of  germinating  seeds.  —  References : 
Osterhout's  Experiments  with  Plants,  Chapters  I  and  II. 
See  also  Atkinson's  books,  and  those  by  Bergen. 

156,  157.  Twigs  and  buds.  —  Ganong,  1910,  pp.  297- 
300.  Cornell  Nature-Study  Leaflets.  Comstock's  Hand- 
book of  Nature-Study. 

161.  Growth  of  monocotyledonous  stems.  —  Bamboo 
stems  grow  in  height  from  one  to  three  feet  a  day  and  a 
stem  twenty  feet  high  may  grow  in  fifty  days,  but  will  be 
soft  and  brittle  like  asparagus  shoots,  and  requires  three 
to  four  years  to  harden.  The  largest  Japanese  species 
grows  fifty  feet  high,  and  five  or  six  inches  in  diameter. 

166.  Grafting    should    be    demonstrated    on    seedling 
apple  trees,  which  may  be  taken  to  the  schoolroom,  grafted, 
and  then  planted ;    or  specimens  showing  various  stages 
(including  growth  after  grafting)  should  be  preserved  dry 
or  in  formalin. 

Reference:  " Top- Working  Orchard  Trees,"  Yearbook 
Reprint  266,  1902,  good  account  of  grafting. 

167.  Pruning.  —  Small    specimens    of    wild    seedling 
apple  trees  or  other  useless  trees  may  be  taken  to  the 
schoolroom    for    demonstrating    principles    of    pruning. 
Specimens  taken  a  year  after  pruning  and  showing  heal- 
ing are  useful.     Reference:  "Pruning,"  (Farmers1  Bulletin 
181). 

169.   Paragraph  3.  —  Correct  spelling  is  lenticels. 

170-178.  Stems.  —  Examples  of  special  stem  adapta- 
tions should  be  collected  and  preserved  dry  or  in  formalin 
solution,  for  use  in  illustrating  the  text-book. 

180.  Forestry.  —  References:  " Forestry  in  Nature- 
Study"  (Farmers'  Bulletin  468)  ;  Roth's  First  Book  of  For- 
estry (Ginn  and  Co.) ;  Pinchot's  Primer  of  Forestry  (Farmers' 


SEED-PLANTS  45 

Bulletins  173  and  358,  also  for  sale  cloth  bound  at  35  cents 
each).  Forest  Service  Circulars:  69  ("Planting"),  130 
("  Forestry  in  Public  Schools  ") ,  157  ("  Conservation") .  See 
list  of  pamphlets  in  Circular  19  on  Publications  for  Use  of 
Teachers  (U.S.  Dept.  Agriculture). 

185.  Flowers  and  leaves.  —  Note  that  the  text  of  the 
Applied  Biology  reads  that  certain  parts  of  the  flower 
are  "leaf-like."  Strictly  speaking,  petals  and  sepals  may 
be  regarded  as  modified  leaves,  but  stamens  and  pistils  are 
probably  not  homologous  with  or  derived  from  green  leaves. 
See  Ganong,  1899,  pp.  147,  236;  or  1910,  pp.  230,  352. 

188.  Clover  leaves  are,  from  the  beginner's  standpoint, 
palmately  compound;    but  in  some  species  the  central 
leaflet  is  stalked  so  as  to  make  a  pinnate  trifoliate  leaf. 
Some  authors  describe  them  as  "digitate." 

189.  Fertilization  and  embryology.  —  This  topic  has  been 
presented  in  the  Applied  Biology  stripped  of  all  the  unessen- 
tial technicalities  which  appeal  to  a  plant  embryologist  or 
to    a   cytologist.      Elementary    botany   for    high-school 
education   is    a   questionable   place   for   introduction  of 
nucellus,  embryo-sac,  chalaza,  micropyle,  synergidae,  polar 
nuclei,  antipodal  cells,  secondary  nucleus  of  the  embryo 
sac,  pro-embryo,  suspensor,   hypophysis,  and  other  em- 
bryological  details ;  not  to  mention  chromosomes,  reducing 
divisions  and   similar  cytological   points  which  may  in- 
terest the  very  advanced  student. 

With  regard  to  the  theory  of  alternation  of  generations 
of  angiosperms,  it  is  all  very  interesting  to  advanced 
students  in  college  classes  in  botany  to  trace  this  splendid 
series  of  homologies ;  but  it  is  nonsense  to  attempt,  with 
high-school  classes,  to  homologize  pollen-grain  and  micro- 
spore,  embryo-sac  and  megaspore,  ovule  and  macrosporan- 
gium,  male  gametophyte  with  contents  of  pollen-tube, 
female  gametophyte  with  contents  of  embryo-sac,  en- 
dosperm and  prothallium. 


46  TEACHERS'  MANUAL  OF  BIOLOGY 

Double  fertilization.  —  It  is  certainly  best  in  elementary 
work  to  omit  reference  to  endospermic  fertilization.  As 
is  well  known,  the  antheridial  cell  in  a  ripe  pollen-grain 
forms  two  sperm-cells,  which  move  down  the  pollen-tube. 
The  nucleus  of  one  of  these  unites  with  the  egg-nucleus 
in  fertilization,  while  the  nucleus  of  the  other  sperm-cell 
has  in  some  plants  been  seen  to  unite  with  the  two  nuclei 
in  the  embryo-sac,  thus  producing  endospennic  fertiliza- 
tion. To  make  this  clear  to  students  means  unwarranted 
detail,  which  will  certainly  tend  to  confuse  beginners. 
The  text  of  the  Applied  Biology  has  been  deliberately 
worded  to  avoid  mentioning  that  there  are  two  sperm- 
cells  or  fertilizing  cells  in  the  pollen  tube ;  and  it  is  simply 
stated  that  a  cell  fertilizes  the  egg-cell.  Thus  elementary 
study  may  escape  the  complicated  problems  of  endosper- 
mic fertilization,  which  may  safely  be  left  for  college  botany. 
Moreover,  this  double  fertilization  is  not  known  to  occur 
in  numerous  species,  and  elementary  biology  should 
center  attention  on  the  typical  aspects  of  fertilization. 

189.  Stamens  and  pistils  as  "male"  and  "female 
organs."  —  The  older  botanical  books  refer  to  stamens 
as  the  "male"  reproductive  organs  and  the  pistils  as  the 
"female."  This  usage  is  now  criticized  because  com- 
parative botany  has  made  clear  that  the  stamen  is  a 
microsporophyll  and  the  pistil  is  composed  of  one  or 
more  carpels  or  megasporophylls.  Likewise,  each  anther 
is  composed  of  microsporangia  (pollen-sacs) ;  and  each 
carpel  bears  megasporangia  (ovules).  Within  each  pollen- 
grain  (microspore)  is  the  antheridium-cell  that  produces 
the  generative  or  sperm-cell.  Within  each  ovule  there  is 
the  embryo-sac  or  megaspore.  This  forms  the  arche- 
gonium  of  the  gymnosperms  and  the  corresponding  egg- 
apparatus  of  the  angiosperms,  and  these  are  the  organs  for 
producing  egg-cells.  Obviously,  in  terms  of  comparative 
botany,  the  antheridium-cell  in  the  pollen-grain  and  the 


SEED-PLANTS  47 

archegonium  or  egg-apparatus  in  the  ovary,  represent 
the  real  sex-organs;  and  the  male  and  female  reproduc- 
tive organs  are  hidden  within  the  stamens  and  pistils. 

Such  are  the  detailed  facts  from  the  point  of  view  of 
comparative  botany;  and  beyond  question  they  should 
be  so  taught  to  advanced  students  of  college  botany.  But 
some  recent  authors  have  attempted  to  transplant  this 
modern  plant  morphology  to  the  high  school,  and  we 
read  in  text-books  that  "  stamens  are  not  male  organs  and 
pistils  are  not  female  organs,"  and  "  pollen-grains  are 
asexual  spores,"  and  "the  carpels  with  ovules  do  not 
represent  female  sex-organs."  All  this  is  true,  but  absurd 
from  the  standpoint  of  99  per  cent  of  high-school  students. 
It  is  plant  morphology  run  amuck  in  general  education. 
What  does  the  average  intelligent  citizen  care  concerning 
the  homologues  of  the  antheridium  or  the  archegonium  ? 
Certainly  those  interested  only  in  the  general  results  of 
science  will  continue  to  regard  stamens  and  pistils  as  sex- 
organs  because  they  are  the  obvious  organs  that  produce 
the  male  and  female  generative  cells.  Plant  morphol- 
ogists  will  not  soon  convert  the  general  student  to  the 
strict  botanical  terminology,  for  only  those  who  have  the 
advantage  of  an  extensive  comparative  course  in  botany 
can  possibly  understand  why  the  ovary  and  anther  of 
spermaphytes  are  not  in  the  strict  botanical  sense  sex- 
organs,  but  that  these  are  developed  somewhere  inside  of 
what  is  called  the  "ovary."  ^Such  quibbles  about  intri- 
cate phylogenetic  homologies  are  quite  beyond  the  under- 
standing and  interests  of  average  students.  This  kind 
of  scientific  hair-splitting  is  well  adapted  to  making 
science  study  mysterious,  useless  in  daily  life,  and  con- 
sequently unpopular.  What  the  average  citizen  of 
general  culture  will  remember  after  the  most  strict  in- 
sistence upon  terminology  is  that  ovaries  in  both  plants 
and  animals  are  organs  for  producing  egg-cells  or  female 


48  TEACHERS'  MANUAL  OF  BIOLOGY 

reproductive  cells,  and  that  the  organs  variously  termed 
spermaries,  anthers,  etc.,  are  organs  for  producing  male 
reproductive  cells  (sperm-cells).  These  are  the  essential 
facts,  and  the  intricate  details  of  histological  structure 
and  its  phylogenetic  interpretation  in  both  plants  and 
animals  may  well  be  left  for  the  advanced  student,  who 
may  reasonably  be  expected  to  comprehend  the  homol- 
ogies. 

However,  it  is  possible  in  an  elementary  course  to  make 
intelligible  the  essential  facts  of  reproduction  in  seed- 
plants  and  yet  partly  to  avoid  the  scientific  quibble  con- 
cerning sex-organs.  Simply  call  the  stamens  and  pistils 
reproductive  organs,  which  is  practically  but  not  phylo- 
genetically  true,  and  use  the  terms  referring  to  sex  only 
when  describing  the  essential  nature  of  the  fertilization 
process  —  a  union  of  two  sex-cells,  one  male  and  one 
female  in  origin.  This  is  the  one  big  idea  in  the  whole 
matter;  and  reasonable  high-school  science  does  not 
need  a  discussion  of  why  stamens  and  pistils  are  not  the 
real  sex-organs  in  modern  botany.  Too  many  teachers 
fresh  from  university  laboratories  have  busied  themselves 
emphasizing  this  criticism  of  the  older  botany,  instead  of 
teaching  the  essential  facts  that  the  average  'cultured 
citizen  needs.  The  rare  high-school  student  who  decides 
to  specialize  in  biology  will  have  abundant  time  for  learn- 
ing in  advanced  college  courses  the  intricacies  of  sex- 
organ  homologies. 

196.  Tubular  flowers.  —-  The  modern  view  (Ganong, 
1899,  pp.  148,  237 ;  or  1910,  p.  235)  that  the  tube  of  a 
tubular  calyx  or  corolla  is  not  a  union  of  sepals  or  petals, 
but  a  ring  of  new  tissue  surmounted  by  the  free  sepals 
or  petals,  means  absolutely  nothing  to  young  students 
and  to  those  unfamiliar  with  morphological  development 
of  plant  structure.  It  is  not  advisable  to  confuse  ele- 
mentary work  by  attempting  such  explanations.  The 


SEED-PLANTS  49 

observable  fact  is  that  the  sepals  and  petals  do  appear 
united,  and  it  is  morphological  quibbling  to  try  to  inform 
beginners  that  the  parts  are  not  united  but  that  a  tubular 
ring  grew  beneath  the  true  petals  or  sepals. 

202.  Ovary  inferior. — See  note  on  §  185.  Also  Ganong, 
1899,  p.  148,  or  1910,  p.  235,  on  the  "  calyx-adnate " 
theory. 

207.  In  legend   of   Fig.   67  transpose  words  to  read 
"Flowers  of  the  composite  Arnica." 

208.  References:  "Annual  Flowering  Plants"  (Farmers' 
Bulletin  195).     " Beautifying  Home  Grounds"  (Farmers' 
Bulletin  185}. 

212-216.  Fruits.  —  The  authors  of  the  Applied  Biology 
have  departed  somewhat  from  the  usual  classification  of 
fruits,  because  they  have  found  the  subject  most  interest- 
ing under  the  headings :  simple  dry  fruits,  simple  fleshy 
fruits,  stone-fruits,  complex  fleshy  fruits;  applying  the 
adjective  simple  to  those  derived  from  ovary,  and  com- 
plex to  combinations  of  ovary  and  surrounding  parts. 

Educational  experiments  are  needed  to  determine 
methods  of  making  study  of  fruits  interesting.  At 
present,  it  is  certainly  a  topic  in  botany  that  competes 
with  bones  in  anatomy.  Probably  the  greatest  interest 
of  students  will  be  found  if  fruits  are  studied  in  relation  to 
flowers  and  along  economic  lines.  Fortunately,  all  materials 
needed  to  illustrate  types  of  fruits  may  be  obtained  from 
markets,  or  preserved  dry  and  in  formalin  solution. 

Preserve  in  2  to  5  per  cent  solution  of  formalin  various 
stages  from  flower  to  perfectly-shaped  fruits  of  apple, 
quince,  strawberry,  buttercup,  tomato,  gooseberry,  cherry 
or  peach,  walnut  or  hickory-nut,  raspberry,  blackberry, 
cucumber  or  squash,  sunflower,  buckwheat,  oak,  chest- 
nut burr,  horse-chestnut,  or  buckeye.  A  series  of  stages 
mounted  as  suggested  by  Lloyd,  1904,  p.  226,  are  desirable. 

See  Ganong,  1910,  pp.  377-380. 


50  TEACHERS    MANUAL  OF  BIOLOGY 

216.  Inferior  ovary.  —  For  the  interpretation  of  sur- 
rounding receptacle  and  not  adnate  calyx,  see  Ganong, 
1899,  bottom  of  p.  147,  or  1910,  p.  235. 

217.  Seed-dispersal.  —  Reference  for  teachers  :  Ganong, 
1910,  272-276. 

218.  Reference:    "Propagation  of  Plants"  (Farmers' 
Bulletin  157). 


CHAPTER  IX 
SPORE-PLANTS 

223.  Ferns.  —  In  the  opinion  of  many  biologists,  ferns 
do  not  deserve  more  time  in  a  year's  course  than  that 
required  for  §§  223-229.     Teachers  who  want  to  provide  for 
more   extensive   study   are   certainly   familiar   with   the 
many  excellent  text-books  of  botany  such  as  Atkinson's 
Botany  for   Schools,   Bergen's   Foundations,   Bergen   and 
Caldwell's  Practical  Botany,   Clute's  Laboratory  Botany. 
Sedgwick  and  Wilson's  General  Biology  has  an  extensive 
account  of  Pteris  in  all  its  biological  aspects. 

224.  Fern  prothallia  may  be  found  at  most  commercial 
greenhouses,  but  may  be  grown  in  the  schoolroom.     A 
shallow  flower-pot  with  a  mixture  of  garden  soil,  leaf- 
mold  and  sand  should  be  heated  in  a  sterilizer  (p.  256  in 
Applied  Biology)  for  a  half-hour  to   destroy    organisms 
that  might  interfere  with  the  young   ferns.     Level   and 
pack  the  surface  of  the  soil,  wet  with  boiled  water,  and 
scatter  but  do  not  cover  spores.     (Spores  may  be  obtained 
from  seed-dealers  or  collected  from  leaves  placed  in  paper 
bags  when  sporangia  begin  to  be  light  brown  and  dry. 
Spores  will  keep  for  years  in  air-tight  jars.)     Cover  the 
pot  so  as  to  protect  against  evaporation.     Keep  the  soil 
moist  without  sprinkling  its  surface  for  several  weeks, 
but  set  the  pot  in  a  saucer  with  water.     Complete  direc- 
tions are  in  Bailey's  Cyclopedia  of  Horticulture,   which 
many  libraries  and  most  up-to-date  gardeners  own. 

228.  Allies  of  ferns.  —  For  supplementary  work  see 
the  text-books  by  Atkinson,  Bergen  and  Caldwell,  and 
Coulter.  A  year's  course  will  not  allow  time  for  more 

51 


52  TEACHERS'   MANUAL   OF  BIOLOGY 

than  brief  demonstrations  of  specimens  selected  to  illus- 
trate the  chief  types. 

229.  Ferns  in  coal.  —  Most  fern-like  fossils  of  the  coal 
are  "seed-ferns"  (Cycadofilicales)  which  combine  character- 
istics of  the  ferns  and  gymnosperms.  The  equisetales,  the 
lycopods,  and  other  fern  allies  are  very  abundant  in  coal. 

230-234.  Moss.  —  References  to  same  authors  as  for 
ferns  (§§  223-228). 

235.  Algce  and  Fungi.  —  The  simplest  possible  classi- 
fication of  lower  cryptogamic  plants  has  been  used  in  the 
Applied  Biology  because  the  division  of  Thallophyta  into 
the  classes  Chlorophyceae,  Charophyceae,  etc.,  of  the 
Algae;  and  Phycomycetes,  etc.,  of  the  true  Fungi  is  of 
no  value  to  one  who  has  not  time  for  thorough  study  of 
types  of  the  ten  or  eleven  classes  of  Thallophytes.  Such 
a  sub-division  is  as  useless  to  the  average  intelligent 
citizen  as  is  the  detailed  classification  of  the  "  worms " 
and  Crustacea  in  zoology. 

237-239.  Unicellular  plants.  —  Laboratory  work  on 
these  sections  should  be  illustrative  of  the  text  in  the 
Applied  Biology. 

238.  Volvox,  Fig.  95,  §   279,  in   the  Applied  Biology, 
should  be  mentioned  here  as  composed  of  numerous  indi- 
viduals,   each   similar   to   Sphserella,   set  in  the  surface 
of  a  hollow,  transparent  sphere.     It  is  a  colony  of  indi- 
viduals, probably  plants. 

239.  Necessary  elements  from  compounds.  —  Page  250, 
ninth  line,  in  the  Applied  Biology,  should  read  "absorb 
compounds  containing  the  necessary  elements  (N,  S,  P,  K, 
etc.)."      Of  course,  not  the  pure  elements,  as  misleadingly 
suggested  by  the  omission  of  the  word  "compounds." 

244.  Molds.  —  For  the  laboratory  work  in  this  section, 
moist  slices  of  bread  should  be  placed  in  covered  dishes 
(e.g.,  in  glass  tumblers  covered  with  3X4  plates  of  glass) , 
some  one  and  some  three  weeks  in  advance,  and  spores 


SPORE-PLANTS  53 

from  a  piece  of  moldy  bread  scattered  over  the  surface. 
Protect  against  bright  light.  Larger  pieces  may  be  laid 
on  moist  blotting-paper  on  a  dinner-plate,  and  covered 
with  another  plate  inverted,  or  with  a  battery-  or  bell- 
jar.  Cultures  may  easily  be  made  almost  pure  by  fol- 
lowing the  directions  on  p.  256  of  the  Applied  Biology. 

When  tumblers  are  arranged  as  suggested  above,  the 
3X4  glasses  used  as  covers  will  often  have  numerous 
spores  attached  to  the  lower  surface  and  in  various  stages 
of  germination.  Examine  such  a  glass  with  low  power  of 
microscope. 

Spores  may  be  germinated  in  drops  of  diluted  sugar 
sirup  on  glass  object-slides.  Keep  the  slides  in  a  covered 
dish  along  with  wet  cotton  or  paper  to  guard  against 
drying.  Do  not  put  on  cover-glass  until  ready  to  study 
with  high-power  lenses. 

246.  Ergot.  —  On  third  line  of  p.  262  in  the  Applied 
Biology  change  to  read  "A  fungus  of  rye."  Ergot  is 
often  called  "smut";  but  it  is  better  to  limit  that  word 
to  corn  smut  and  other  species  of  Ustilago. 

Economic  fungi.  —  References  :  "Fungicides"  (Farmers' 
Bulletin  248),  "Rusts  of  Grains"  (Bulletin  216,  Bureau  of 
Plant  Industry),  Weed's  Farm  Friends  and  Foes,  Part  III 
(Heath  and  Co.). 

249.  Mushrooms.  —  Reference  :  "Cultivation  of  Mush- 
rooms" (Farmers'  Bulletin  204)-  Other  references  are 
given  on  page  267  of  the  Applied  Biology. 

251.   Pasteur's  solution  contains  the  following  ingredients : 

PER  CENT 

Water,  H20 83.76 

Cane  sugar,  Ci2H220n 15.00 

Ammonium  tartrate  (NH^C^Oe 1.00 

Potassium  phosphate,  K3PO4      .......  0.20 

Calcium  phosphate,  CasCPO^ 0.02 

Magnesium  sulphate,  MgS04 0.02 

100.00 


54  TEACHERS'  MANUAL  OF  BIOLOGY 

The  author  has  often  found  it  inconvenient  to  make 
up  the  Pasteur's  solution  when  needed  and  he  now  keeps 
in  stock  some  small  packages  containing  all  the  constit- 
uents (except  sugar)  mixed  ready  for  adding  water.  A 
package  to  make  one  quart  of  the  solution  will  be  mailed 
by  the  author,  only  to  teachers  who  use  the  Applied 
Biology,  for  twelve  cents,  actual  cost  of  chemicals,  prepa- 
ration, and  postage. 

Vacuoles.  —  In  legend  of  Fig.  83,  Applied  Biology,  1911, 
add  "  clear  centers  contain  fluid." 

Yeast.  —  The  experiments  outlined  in  this  section  of 
the  Applied  Biology  are  usually  impracticable  for  individ- 
ual work  in  high  schools  with  large  classes,  and  the 
possibilities  of  error  are  so  great  that  the  demonstration 
method  is  preferable.  The  teacher  should  have  the  pupils 
take  notes  as  the  demonstrations  proceed.  After  the 
facts  are  recorded,  go  back  to  compare  the  tubes  and  to 
draw  conclusions.  The  facts  are  for  the  seven  tubes  as 
follows :  No.  1  (pure  water),  no  growth,  no  fermenta- 
tion; No.  2  (pure  sugar  solution),  no  growth,  some  fer- 
mentation ;  No.  3  (sugar  with  meat  extract),  much  growth, 
much  fermentation;  Nos.  4  (crude  molasses),  5  (flour 
paste),  7  (Pasteur's  solution),  almost  the  same  as  No.  3 
in  growth  and  fermentation;  No.  6  (Pasteur's  solution 
without  sugar),  growth  of  yeast,  but  no  fermentation. 
Conclusions  are :  No.  1 ,  no  food  for  growth  and  no  sugar 
for  fermentation ;  No.  2,  sugar  for  fermentation,  but  not 
sufficient  food  for  growth ;  No.  3,  the  beef-extract  evi- 
dently adds  to  No.  2  material  for  growth,  making  more 
yeast-plants  and  consequently  more  fermentation  of  the 
sugar;  No.  4,  dark-colored  molasses  evidently  has  some- 
thing for  growth  in  addition  to  sugar  used  in  No.  2.  The 
sugar  used  for  No.  2  is  purified  or  refined,  various  sub- 
stances in  the  crude  sugar  being  removed.  A  solution  of 
very  dark-brown  sugar  will  give  results  similar  to  the 


SPORE-PLANTS  55 

molasses.  Some  substances  in  the  molasses  evidently 
serve  the  same  as  the  meat-extract  in  No.  3.  Tube  5 
shows  that  yeast  can  grow  in  flour  paste  and  ferment  it. 
The  explanation  is  that  an  enzyme  changes  some  of  the 
flour  to  sugar  and  then  sugar  fermentation  by  another 
enzyme  occurs.  Help  students  to  apply  this  experiment 
to  bread-making  by  the  usual  process.  Tube  6  has  a 
solution  of  known  chemical  composition  (see  §  251  in  this 
Manual)  .  Pasteur  found  that  yeast  must  have  for  growth 
carbon,  hydrogen,  oxygen,  nitrogen,  phosphorus,  cal- 
cium, magnesium,  potassium,  and  sulphur  ;  and  the  Pas- 
teur's solution  without  sugar  furnishes  these,  but  there  is 
no  sugar  to  ferment.  Tube  7  furnishes  the  elements 
needed  for  growth  and  also  the  sugar  to  ferment. 

General  conclusions  :  Yeast  may  grow  in  solutions 
without  sugar,  but  sugar  (or  starch  convertible  into  sugar) 
is  necessary  for  fermentation.  Yeast  cannot  grow  in 
pure  sugar  solution,  because  sugar  supplies  only  the  ele- 
ments carbon,  hydrogen,  and  oxygen,  and  six  others  are 


References  for  students  :  Conn,  Bacteria,  Yeasts,  and 
Molds,  1903,  chapters  on  yeast. 

References  for  teachers:  Bigelow,  1904,  pp.  303-305; 
Parker's  Biology,  chapter  on  yeast  ;  Sedgwick  and  Wilson's 
Biology,  lesson  on  yeast. 

253.  Reference:  "  Bread  Making"  (Farmers'  Bulletin 
389). 

256.  Gelatin  media  (p.  280  in  the  Applied  Biology). 
Take  any  commercial  meat  bouillon  or  a  "clear  soup"  sold 
in  ten-cent  cans,  add  a  solution  of  sodium  hydrate  or  bak- 
ing soda  gradually  to  make  the  bouillon  slightly  alkaline 
as  shown  by  bluing  of  red  litmus.  To  one  fourth  pint  of 
the  bouillon  add  an  ounce  of  gelatin;  and  heat  and  stir 
in  a  water-bath  until  gelatin  is  dissolved.  (An  extem- 
porized water-bath  may  be  made  on  the  principle  of  a 


56  TEACHERS'  MAX  UAL  OF  BIOLOGY 

double  cereal-cooker,  by  placing  a  small  tin  can  hold- 
ing the  gelatin  inside  a  larger  one  containing  water.)  If 
the  mixture  is  acid,  add  more  baking  soda  or  sodium 
hydrate  until  slightly  alkaline.  It  is  now  called  nutrient 
gelatin.  It  may  be  stored  in  a  cotton-stoppered  bottle, 
sterilized  30  minutes;  or  it  may  be  distributed  at  once 
into  test-tubes,  flat  bottles,  or  Petri  dishes,  and  then 
sterilized.  Resterilize  after  a  day. 

A  clearer  gelatin  may  be  obtained  by  clarifying  with 
egg-albumen  and  then  filtering  through  a  hot-water 
funnel.  (See  manuals  of  bacteriology  such  as  those  by 
Moore,  Gorham,  Heinemann,  Stitt ;  and  also  some  larger 
text-books,  such  as  Jordan's.) 

Instead  of  sterilizing  media  in  Petri  dishes,  it  is  a  very 
common  practice  to  sterilize  the  dishes  thoroughly  and 
later  to  raise  the  covers  and  pour  in  sterile  melted  gelatin 
from  test-tube  or  a  flask  which  has  been  kept  stoppered 
with  cotton. 

Some  commercial  laboratories  (e.g.,  Parke,  Davis  &  Co. 
of  Detroit)  sell  gelatin  media  in  cotton-stoppered  test- 
tubes  and  in  sterilized  bottles;  but  the  cost  is  too  great 
for  class  work,  being  about  $2  for  a  500  cc.  flask. 

For  very  accurate  study  of  bacterial  growth,  gelatin 
medium  should  be  made  according  to  directions  in  bacteri- 
ological books,  such  as  those  named  above. 

256.  Disinfectants. — Reference:  "Some  Common  Dis- 
infectants" (Farmers1  Bulletin  345).  Chapter  17,  Conn's 
Bacteria,  Yeasts,  and  Molds  in  the  Home,  1903. 

Antiseptics. — The  epoch-making  work  of  Lister,  who 
applied  antiseptic  methods  to  surgery,  should  be  noted  in 
this  lesson. 

258.  Soil  bacteria.  —  References  :  "  Leguminous  Crops  " 
(Farmers'  Bulletin  278).  "Alfalfa"  (Farmers1  Bulletin 
839) .  " Cowpeas "  (Farmers1  Bulletin 318) .  "Soy  Beans " 
(Farmers1  Bulletin  372).  "Red  Clover"  (Farmers1  Bulle- 


SPORE-PLANTS  57 


tin    455}.     ''Canadian    Peas"    (Farmers'    Bulletin 
"Soil   Bacteria"    (Yearbook   Separate  507,    1909).     "Ni- 
trogen-gathering  Plants"  (Yearbook  Separate  530,  1910). 

258.  Milk   and   bacteria.  —  References:    "Bacteria   in 
Milk"  (Farmers'  Bulletin  348) ;  "Care  of  Milk"  (Farmers' 
Bulletin  413).     Also  see  Conn,  1903. 

259.  Germ     diseases.  —  References  :      "  Tuberculosis  " 
(Farmers'  Bulletin  473).     "Typhoid"    (Farmers'  Bulletin 
478).     Conn,  1903.     Sternberg's  Infection  and  Immunity 
(Putnams).     See  also  §  265  below. 

263.  Antitoxins.  —  Emphasize  the  fact  that  no  diph- 
theretic  bacteria,  but  only  their  toxins,  are  injected  into 
the  horse  selected  for  producing  antitoxins.  The  total 
amount  of  diphtheretic  toxins  injected  into  the  horse, 
at  intervals  of  three  to  seven  days  for  several  months, 
is  enough  to  kill  five  hundred  thousand  guinea  pigs, 
weighing  about  a  half-pound  each,  and  one  cc.  of  the 
immunized  horse's  blood  will  contain  enough  antitoxin 
to  neutralize  the  amount  of  toxin  that  would  kill  fifty 
thousand  guinea  pigs. 

265.  Books  on  bacteria.  —  In  addition  to  the  books 
suggested  at  the  bottom  of  p.  297,  in  the  Applied  Biology, 
Marshall's  Microbiology  has  a  good  general  account  of 
bacteria.  Newman's  Bacteria  is  good,  but  needs  revision. 
See  list  cited  by  Bigelow,  1904,  p.  423.  Farmers'  Bulletin 
449  is  on  hydrophobia. 


CHAPTER  X 
PROTOZOA 

266-367.  Order  of  study.  —  The  authors  of  the  Applied 
Biology  recognize  that  many  teachers  might  have  more 
success  if  the  vertebrates  followed  the  earlier  frog  study 
directly,  instead  of  this  chapter  on  one-celled  animals. 
The  arguments  by  Bigelow,  1904.  pp.  345-352,  in  favor  of 
beginning  zoology  by  studying  complex  before  simple 
animal  types  do  not,  of  course,  apply  to  Chapter  X  of 
the  Applied  Biology,  because  the  frog  study  of  Chapter  IV 
has  preceded  as  an  introductory  study. 

266-279.  Protozoa.  —  Concerning  the  difficulties  of 
beginning  work  with  these  animals,  see  Bigelow,  1904, 
pp.  345-352.  Comparison  with  complex  animals,  pp. 
379,  380.  Materials  and  methods,  pp.  363,  394-397. 

References  on  Protozoa  will  not  be  so  useful  as  those  on 
other  groups,  for  the  Applied  Biology  probably  will  require 
as  much  time  on  those  animals  as  can  be  assigned  in  most 
high  schools.  However,  Linville  and  Kelly,  1906,  pp. 
280-291;  Jordan  and  Heath,  1902,  11-18;  Davenport, 
1911,  280-288;  and  Kellogg,  1901,  81-89;  will  be  satis- 
factory for  students.  Teachers  will  find  chapters  on 
Protozoa  in  Parker's  Elementary  Biology,  Parker  and 
Parker's  Practical  Zoology,  Sedgwick  and  Wilson's  General 
Biology,  as  well  as  in  all  zoologies.  Calkin's  Proto- 
zoology is  more  useful  than  his  earlier  The  Protozoa. 

266.  Frog  and  protozoans.  —  It  may  be  said  that  after 
study  of  plant  life  in  Chapters  V-VIII  the  students  have 
forgotten  much  of  their  study  of  the  frog  in  earlier  chapters. 

^ 


PROTOZOA  59 

This  is  probably  true,  but  it  is  of  little  significance.  Stu- 
dents in  the  second  half-year  of  any  course  forget  much 
they  learned  in  the  first  half ;  but  the  efficient  teacher  has 
little  difficulty  in  reviewing  and  recalling  the  essential  facts 
which  may  have  become  more  or  less  dormant  in  memory. 

One  strong  argument  for  not  going  directly  from  the 
frog  to  the  other  types  of  animals  is  that  the  interval 
allows  the  students  time  to  assimilate  many  essential 
ideas  and  to  forget  more  or  less  trivial  facts ;  and  when  the 
great  principles  of  zoology  that  the  frog  illustrates  are 
brought  up  afresh  in  connection  with  other  animal  types, 
a  fixed  and  definite  impression  will  probably  be  made. 

267.  Paramecium.  —  In  order  to  use  the  high  power 
of  the  microscope  for  the  study  of  details  of  structure, 
it  is  necessary  to  impede  locomotion  of  the  paramecia 
by  shreds  of  cotton,  or  by  adding  a  mucilage  made  of 
gelatin  or  gum  arabic  to  the  water  (see  directions  given 
by  Bigelow,  1904,  p.  396). 

For  other  practical  points  concerning  study  of  Para- 
mecium, see  Bigelow,  1904,  pp.  363,  379,  395-397. 

Conjugation.  —  In  elementary  study,  it  is  certainly  best 
not  to  mention  the  details  of  nuclear  activity  in  this 
process.  Dr.  Woodruff,  of  Yale  University,  has  obtained 
more  than  2900  generations  of  Paramecium  without  con- 
jugation occurring.  Hay-infusion  cultures,  kept  in  fruit- 
jars  and  examined  every  few  days,  will  probably  develop 
an  "epidemic  of  conjugation"  within  a  month  or  two. 

270.  Amoeba.  —  According  to  Professor  A.  H.  Cole, 
of  the  Chicago  Normal  School,  amcebas  may  be  reared 
in  a  culture  fluid  such  as  Sach's  solution.  Tablets  for 
making  this  may  be  obtained  for  ten  cents  from  the 
Agassiz  Association,  Sound  Beach,  Conn.  The  tablets 
should  be  dissolved  in  pond  water  and  various  water 
plants  added.  See  details  in  Cole's  Manual  of  Biological 
Projection  (Neeves  Co.,  Sixty-third  St.,  Chicago). 


60  TEACHERS'  MANUAL  OF  BIOLOGY 

When  referring  to  the  genus  Amoeba,  a  capital  is  proper, 
but  "an  amoeba"  or  "amcebas"  are  used  by  good  au- 
thorities when  referring  to  individuals.  Likewise,  we 
write  Hydra  (§  282)  for  the  genus,  but  hydras  for  in- 
dividuals ;  and,  among  plants,  Viola  the  genus  and  violet 
the  species,  Chrysanthemum  the  genus,  and  chrysan- 
themums the  varieties  or  individuals.  For  convenience, 
the  same  anglicizing  of  numerous  botanical  and  zoologi- 
cal taxonomic  names  is  needed. 

On  materials  and  methods  see  also  Bigelow,  1904,  pp. 
379,  380,  394.  Good  permanent  preparation  of  amcebas 
may  be  purchased  at  50  cents  a  slide  from  F.  D.  Barker, 
Station  A,  Lincoln,  Neb.  The  chief  value  of  such  slides 
is  in  showing  nucleus.  Amcebas  are  most  interesting 
because  of  protoplasmic  movements.  Hence  living  speci- 
mens are  important.  The  same  dealer  has  sent  them  alive 
by  mail  to  New  York  City. 

278.  Vorticella  allies.  —  Examples  of  colonial  Vor- 
ticella-like  protozoans  are  described  in  Parker's  Ele- 
mentary Biology  and  in  Parker  and  Haswell's  Zoology. 


CHAPTER  XI 

POBIFERA    AND    CcELENTERATA 

281.  Fresh-water   sponges    (Spongilla)    should    be    ex- 
hibited, if  possible,  but  are  too  complicated  for  elementary 
study.     Also,  specimens  of  glass  sponges  will  add  interest. 

References:  Linville  and  Kelly,  1906,  pp.  273-279; 
Kellogg,  1901,  pp.  90-97. 

282.  Hydra.  —  References  for  teacher  :    Bigelow,  1904, 
pp.  363,  381,  397-400;    Parker's  Elementary  Biology. 

282-292.  Codenterates.  —  Concerning  selection  of  types, 
see  Bigelow,  1904,  pp.  363,  364.  Outline  of  study,  pp. 
381,  382.  Materials,  pp.  397-400. 

References  for  students :  Linville  and  Kelly,  1906,  pp. 
252-272 ;  Jordan  and  Heath,  1902,  pp.  29-43 ;  Kellogg, 
1901,  pp.  98-113;  Davenport,  1911,  pp.  260-279. 

For  full  bibliography  of  zoological  books,  cited  by  author 
and  date,  see  pp.  90-101  in  this  Manual. 


61 


CHAPTERS  XII  AND  XIII 

"WORMS"    AND   ECHINODERMS 

293.  "Worms."  -  Certain  representatives  of  that  vast 
and  heterogeneous  assemblage  of  animals  once  involved 
in  the  now  obsolete  phylum  Vermes  are  of  such  great  im- 
portance that  biology  for  general  education  must  include 
them.  And  yet  they  are  most  puzzling  in  elementary 
zoology,  for  the  fact  that,  in  popular  language,  they  are 
"wormlike"  is  the  only  thing  that  groups  together  for 
beginners  the  utterly  diverse  types  platyhelminthes,  nema- 
thelminths,  and  annelids.  Hence,  examples  of  "worm>  ' 
should  be  studied  by  beginners  simply  from  the  point  of 
view  of  applied  biology ;  and  we  must  frankly  admit  that 
their  comparative  morphology  and  taxonomy  are  quite 
beyond  any  but  advanced  students. 

The  author  believes  that  the  popular  names  of  worms 
(flat  worms,  round  worms,  and  segmented  worms)  are 
sufficient  for  elementary  applied  biology;  but  students 
of  classical  languages  may  be  interested  in  the  three  techni- 
cal names  that  are  literally  translated  flat  worms,  thread 
worms,  and  ringed  worms,  also  in  the  term  helminthology 
from  helminth,  meaning  a  worm.  The  references  given 
below  are  general  accounts  most  useful  at  the  close  of  the 
study  of  "worms." 

References  for  students  :  Davenport,  1900,  pp.  151-158 ; 
Davenport,  1911,  pp.  191-197;  Linville  and  Kelly,  1906, 
pp.  222-235 ;  Jordan  and  Heath,  1902,  pp.  44-71 ;  Kellogg, 
1901,  pp.  133-150. 

297.  Trichina.  —  Reference  :  "Trichinosis"  (Circular 
108,  Bureau  of  Animal  Industry). 

62 


"  WORMS  "    AND   ECHINODERMS  63 

300.  Annelids,  —r  While  metameres  are  mentioned  in 
the  Applied  Biology,  the  author  questions  whether  a  dis- 
cussion of  the  principle  of  metamerism  should  be  introduced 
to  high-school  students,  even  after  comparative  study  of 
various    animals.     Merely    the    fact    that    earthworms, 
Crustacea,   insects,   etc.,   are    segmented    should  be  em- 
phasized,    The   synonym   somite   for   metamere   is   pre- 
ferred by  some  zoologists. 

301.  Nereis  is  interesting  for  comparison  with  the  earth- 
worm, which  in  adaptation  to  burrowing  in  soil  has  not 
prominent  appendages  like  those  of  the  sandworm. 

References  for  students  :  Davenport,  1900,  pp.  145-151, 
or  1911,  pp.  182-189;  Linville  and  Kelly,- 1906,  pp.  222- 
223. 

302.  Earthworm.  —  Materials  :  Bigelow,  1904,  pp.  400- 
404.     Its  value  as  a  type,  same  author,  p.  360. 

There  should  be  only  as  much  study  of  the  internal 
organs  of  the  earthworm  as  is  needed  for  appreciation 
of  the  general  physiological  processes.  All  details,  such 
as  locating  organs  in  numbered  segments,  may  well  be 
omitted  from  elementary  zoology. 

A  lesson  on  the  physiology  of  the  earthworm  may  be 
added  if  time  allows.  See  Linville  and  Kelly,  1906,  pp. 
196-208;  or  (for  teachers  only)  Sedgwick  and  Wilson. 
Ecology  of  earthworm  :  Linville  and  Kelly,  1906,  pp.  218- 
221. 

References  for  students  :  Davenport,  1900,  pp.  133-136  ; 
Davenport,  1911,  pp.  168-172;  Kellogg,  1901,  pp,  133- 
144;  Linville  and  Kelly,  1906,  pp.  195-221.  .At  close  of 
lesson  on  earthworms,  Chapter  XI  (pp.  161-167)  in 
Davenport,  1911,  may  be  assigned  for  reading,  or  outlined 
by  the  teacher. 

Reference  for  teachers  :  Sedgwick  and  Wilson 's  General 
Biology. 

303.  Development  of  earthworm.  —  For  teacher,   Sedg- 


64  TEACHERS'   MANUAL   OF  BIOLOGY 

wick  and  Wilson,  or  Linville  and  Kelly  (pp.  209-217) 
give  the  essential  facts  and  diagrams. 

305.  Echinoderms.  —  The  author  sees  no  reason  for 
change  in  the  opinion  formerly  expressed  (Bigelow,  1904, 
pp.  365,  386)  that  echinoderms  deserve  little  emphasis  in 
an  elementary  course  of  biology  or  zoology.  The  school 
should  have  museum  specimens,  in  formalin  or  alcohol, 
of  American  representatives  of  each  of  the  five  classes. 
The  prices  for  good  single  specimens  are  reasonable. 
They  may  be  purchased  from  the  biological  laboratories 
at  Woods  Hole,  Mass.,  South  Harpswell,  Me.,  and  other 
dealers  (see  Appendix  III). 

References  for  students:  Kellogg,  1901..  pp.  114-132; 
Jordan  and  Heath,  1902,  pp.  140-150 ;  Linville  and  Kelly, 
1906,  pp.  236-251 ;  Colton,  1903,  pp.  331-347 ;  Jordan, 
Kellogg  and  Heath,  1903,  pp.  150-160 ;  Davenport,  1900, 
pp.  192-204;  Davenport,  1911,  pp.  246-259. 


CHAPTER  XIV 
ARTHROPODS 

309.  Peripatus.  —  The  class  Onychophora  (genus  Peri- 
patus)  is  omitted  from  the  text  of  the  Applied  Biology 
because  of  interest   chiefly  in  morphological   and  phy- 
logenetic  interpretations  that  are  beyond  beginners  in 
zoology. 

310.  Crayfish.  —  The  value  of  this  animal  for  elemen- 
tary laboratory  study  is  discussed  by  Bigelow,  1904,  p. 
358 ;  an  outline  study,  pp.  372-378 ;  concerning  specimens 
for  study,  pp.  404-406. 

Dealers,  1910 :  The  author  deals  with  Burns,  Chicago, 
and  Knoll,  New  York  (see  list  in  Appendix  III).  Prob- 
ably dealers  in  markets  of  most  large  cities  can  supply 
crayfishes  in  the  autumn, 

Homology.  —  The  principle  of  serial  homology  as  il- 
lustrated by  crayfish  appendages  may  be  briefly  presented, 
but  probably  means  little  to  most  beginners.  Certainly, 
comparison  of  the  first  five  pairs  of  appendages  is  useless 
in  high  schools. 

Gill-currents  are  best  shown  by  placing  a  crayfish  on 
its  back  in  one  inch  of  water.  Hold  firmly  but  gently  until 
quiet  ("pseudo-hypnotism"),  then  release  pressure  and 
drop  with  a  pipette  some  "carmine-water"  near  the  last 
legs.  Other  finely  divided  insoluble  pigments  such  as 
lampblack,  India  ink,  gamboge  mixed  with  water  may  be 
used. 

References  for  students :  Davenport,  1900,  pp.  97-122  ; 
Davenport,  1911,  Chapter  IX;  Kellogg,  1901,  pp.  18-27, 
F  65 


66  TEACHERS'  MANUAL   OF  BIOLOGY 

153-154,  159-162;   Jordan,  Kellogg  and  Heath,  1903,  pp. 
116-118;   Linville  and  Kelly,  1906,  pp.  125-147. 

References  for  teachers :  Andrews,  E.  A.,  Article  on 
"Keeping  and  Raising  Crayfishes/'  in  Nature-Study 
Review,  Dec.,  1906,  pp.  296-301;  also  on  "Crayfish 
Industry"  in  Science,  June  29,  1906.  Other  references  are 
given  by  Bigelow,  1904,  p.  375. 

315.  References  for  students :    Davenport,    1900,   pp. 
111-118;    Davenport,   1911,  pp.  135-147;    Linville  and 
Kelly,  1906,  Chapter  XIII. 

316.  References  for  students :  Davenport,  1900,  pp.  125- 
130;   Davenport,  1911,  pp.  153-160;   Linville  and  Kelly, 
1906,  pp.  147-156. 

318.  Spiders  may  be  preserved  in  ethyl  alcohol,  wood 
alcohol,  or  2  or  5  per  cent  formalin  solution.  Since  no  dis- 
section is  required,  specimens  may  be  used  for  several  years. 

Demonstrate  arrangement  of  the  simple  eyes  of  a 
spider  under  microscope.  Emphasize  comparison  be- 
tween spider  and  crayfish  with  regard  to  divisions  of  the 
body,  simple  and  compound  eyes,  number  of  legs,  legs 
with  several  joints,  organs  for  breathing,  external  skeleton, 
appendages  on  abdomen.  A  comparative  table  should 
be  begun  with  three  columns,  one  to  be  filled  out  later 
after  grasshopper  is  studied. 

Habits.  —  Supplementary  nature-study  points  on  spi- 
ders. The  secretion  of  spinning  glands  of  some  species 
forms  webs  for  catching  insects;  in  trap-door  spiders  it 
makes  a  silken  lining  to  tunnels  in  soil  and  the  framework 
of  the  door ;  in  other  species,  it  forms  cocoons  for  eggs ; 
in  others  the  threads  serve  for  uniting  sticks,  leaves,  etc., 
to  make  a  nest ;  in  still  others,  threads  are  used  for  loco- 
motion and  may  even  form  fluffy  silken  masses  by  which 
the  spiders  may  float.  Webs  are  of  several  types ;  see 
Davenport's  Zoology,  or  Emerton's  Spiders. 

Poisonous  effect  of  spider  bites  on  men  and  large  ani- 


ARTHROPODS  67 

mals  is  never  serious.  Bites  of  ordinary  spiders  are  no 
more  dangerous  than  those  of  bees  and  mosquitoes. 

References  for  students :  Colton,  1903,  pp.  54-60  ; 
Davenport,  1900,  pp.  80-95;  Davenport,  1911,  pp.  102^ 
119;  Kellogg,  1901,237-246;  Jordan  and  Heath,  1902, 
pp.  133-139;  Linville  and  Kelly,  1906,  pp.  116-124. 

References  for  teachers:  Hodge,  1902,  pp.  419^22; 
Holtz,  1908,  pp.  246-250 ;  Cornell  Leaflets,  1904,  pp.  65- 
66,  171-183;  Emerton's  Spiders,  Their  Structure  and 
Habits  and  his  Common  Spiders  of  United  States;  Corn- 
stock's  Handbook  of  Nature-Study  (1912).  A  great 
systematic  book  by  Professor  Comstock  is  in  press  for 
publication  in  1912. 

321.  Myriapoda.  —  Centipedes  and  millipedes  are  quite 
different  in  structure  and  some  authors  divide  the  class 
Myriapoda.  Of  course,  such  details  are  absurd  for  ele- 
mentary work. 

323.  Grasshopper.  —  Materials  :   Bigelow,  1904,  p.  407. 
Living  grasshoppers  may  be  kept  in  wire  cages.     Get 
a  piece  of  wire-screen  about  12  X  30  inches,  roll  so  as  to 
form  a  cylinder  about  10  inches  in  diameter  by  12  high, 
and  cap  one  end  with  a  disc  of  wire  screen,  cut  the  same 
diameter  as  the  cylinder.     Fine  copper  or  soft  iron  wire  is 
excellent  for  fastening  the  cap  and  side  of  the  cylinder 
by  sewing  " over-cast"  stitches  through  the  meshes  of  the 
screen.     Such  wire  cylinders  may  be  inverted  over  potted 
plants,  dishes  with  fresh  grassy  sod,  and  other  objects 
suitable  for  insects. 

Good  methods  on  insect  materials  in  general  are  given 
by  Hodge,  1902,  pp.  45-61 ;  and  Comstock's  Nature- 
Study,  1912. 

324.  Lepidoptera.  —  Materials :    Butterflies,    tomato- 
worms  and  other  larvae,-  collected  in  midsummer  and  pre- 
served in  alcohol  or  formalin.     Cocoons  of  large  moths 
(cecropia,    cynthia,    etc.).     They   may   be   preserved   in 


68  TEACHERS'  MANUAL  OF  BIOLOGY 

alcohol  or  formalin.  Excellent  practical  notes  are  given 
by  Dickerson,  1901,  pp.  291-332.  Some  cocoons  with 
living  pupae  should  be  hung  inside  a  cage  described  in 
§  323,  and  the  emerging  moths  will  be  prevented  from 
flying  and  breaking  their  wings.  In  such  cages  cecropia 
and  cynthia  moths  pair  naturally  and  produce  fertile  eggs, 
which  may  be  kept  in  a  box  for  some  days  until  the  larva) 
hatch.  Leaves  of  many  trees  and  shrubs  may  serve  as 
food;  but  no  change  of  diet  should  be  made  after  the 
larvae  begin  on  one  kind  of  leaves.  The  author  has  seen 
cecropia  caterpillars  fed  on  leaves  from  privet  hedges 
and  reared  to  perfect  pupae.  See  Dickerson's  book. 

325.  Cicada.  —  In  the  Southern  States  the  life-history 
is  only  thirteen  years  long.     A  full   and  illustrated  ac- 
count of  the  Cicada  is  in  Bulletin  14  of  the  U.  S.  Bureau 
of  Entomology  (for  sale  by  Supt.  of  Documents,  Wash- 
ington, D.C.).     There  are  also  smaller  pamphlets  avail- 
able free,  especially  annual  circulars  of  the  U.  S.  Dept. 
of  Agriculture,  giving  the  geographical   location  of  ex- 
pected broods. 

326.  Insect  classification.  —  The  grouping  adopted   in 
this  section  of  the  Applied  Biology  is  easily  learned  and 
includes    most    of   the    economically    important    insects. 
The  ten  to  fifteen  additional  orders  adopted  by  various 
modern  entomologists  are  chiefly  of  interest  to  taxono- 
mists.     The  remarks  in  the  paragraph  on  "  netted-winged 
insects"  in  the  Applied  Biology  will  make  it  clear  that 
insect  classification  which  is  more  complicated  than  that 
of  the  important  orders  given  in  this  section  is  undesir- 
able for  elementary  students.     The  principle  determining 
this  simplifying  of  classification  is  stated  by  Bigelow,  1904, 
p.  281. 

Wings  of  Hemiptera  (p.  388  in  Applied  Biology).  —  The 
wings  are  absent  in  bed-bugs,  cochineal-bugs,  and  scale- 
bugs.  There  are  two  wings  in  male  coccids. 


ARTHROPODS  69 

Number  of  insect  species.  —  The  figures  on  pp.  388  and 
389  in  the  Applied  Biology  are  very  conservative  estimates. 
The  fact  is  that  radical  entomologists  consider  as  species 
what  conservative  men  call  varieties.  A  radical  species- 
splitter  would  no  doubt  make  many  species  of  dogs  that 
are  commonly  considered  varieties  or  breeds.  However, 
even  the  lowest  estimates  of  insect  species  are  astounding. 

327.  Useful   insects.  —  Reference:     "Bees"    (Farmers' 
Bulletin  447),  Weed's  Farm  Friends  and  Foes,  Part  II 
(Heath,  1910).     Smith's  Insect  Enemies  and  Friends  (Lip- 
pincott,  1909). 

328.  Injurious  insects.  —  Reference :  See  §  327  above. 

329.  Mosquitoes.  —  References:    "Malaria"    (Farmers' 
Bulletin  450),  "Mosquitoes"  (Farmers'  Bulletin  444).    See 
§  330  below. 

330.  Flies.  —  References  :     "House    Flies"    (Farmers' 
Bulletin  459) ;   "How  Insects  Affect   Health"  (Farmers' 
Bulletin  155).     "Typhoid  Fly"  (Entomology  Bulletin  78) ; 
Doane's  Insects  and  Disease  (Holt,  1910) ;  Howard's,  House 
Fly;  Disease  Carrier  (Stokes,  1911,  $1.50). 

328-330.  Economics  of  Insects.  —  General  references : 
Smith,  J.  B.,  Insect  Enemies  and  Friends  (Lippincott) ; 
Holtz,  1908,  pp.  175-245;  Hodge,  1902,  pp.  62-89,  181- 
274;  Davenport,  1900,  pp.  66-73;  Davenport,  1911, 
Chapter  V;  Cornell  Nature-Study  Leaflets;  Comstock's 
Handbook  of  Nature-Study,  1912. 

Many  valuable  pamphlets  are  issued  by  the  United 
States  Department  of  Agriculture;  see  list  by  Bigelow, 
1904,  p.  428 ;  and  consult  circular  on  agricultural  pam- 
phlets classified  for  use  of  teachers.  Also  consult  appendix 
of  Holtz's  Nature-Study,  1908. 


CHAPTER  XV 

MOLLUSKS 

339.  Snails.  —  The  Helix  pomatia  is  very  common  in 
France  and  Germany  and  is  a  pest  in  gardens  and  vine- 
yards. Its  scientific  name  means  "apple  snail."  Pur- 
chased by  the  hundred,  hibernating  snails  cost  about  $1.50 
in  New  York  from  October  to  April.  A  few  specimens  by 
mail  cost  about  four  cents  each.  The  author  will  gladly 
supply  them  at  cost  to  teachers  who  need  only  a  few  for 
class  work  with  the  Applied  Biology. 

For  methods  of  preparing  specimens  of  snails,  see 
Bigelow,  1904,  p.  406;  or  School  Science,  January,  1903. 

341.  Squid.  —  It  is  more  than  useless,  because  inex- 
tricably confusing,  to  try  to  show  beginners  in  zoology 
that  the  hind-end  (fin-bearing)  of  the  squid  is  dorsal  and 
the   head-end  ventral.     Simply  use  such  terms  as  head- 
end and  hind-end,  upper  and  lower  sides.     For  the  mor- 
phological  comparison  with  other  mollusks,  see  Pratt's 
Invertebrate  Zoology,  1901,  p.  114,  or  zoological  treatises. 

For  discussion  of  value  of  cephalopods  in  elementary 
zoology,  see  Bigelow,  1904,  p.  367. 

342.  Roger's  Shell  Book  is  the  only  general  book  avail- 
able;   but  experts  say  its  text  has  many  errors.     How- 
ever, the  numerous  illustrations  make  it  useful. 


70 


CHAPTER  XVI 

VERTEBRATES 

343.  Classes  of  vertebrates.  —  The  familiar  division  of 
vertebrates  into  five  classes  (fishes,  amphibia,  reptiles, 
birds,  and  mammals)  appeals  to  the  authors  of  the  Applied 
Biology  as  best  for  an  elementary  course  of  zoology.  It 
is  used  by  A.  Sedgwick  in  his  well-known  Student's  Text- 
Book  of  Zoology,  Vol.  II,  1905.  This  is  certainly  best  for 
beginners,  who  could  not  comprehend  such  a  scheme  as 
that  which  recognizes  the  fundamental  distinction  be- 
tween Marsipobranchia  or  Cyclostoma  (lampreys)  and 
true  fishes,  thus  making  an  additional  vertebrate  class. 
(See  Parker  and  HaswelPs  Text-Book  of  Zoology,  Vol.  II,  1897.) 

Likewise,  it  has  seemed  better  in  elementary  zoology 
to  follow  those  authors  (see  Sedgwick)  who  regard  Verte- 
brata  as  a  phylum  and  Chordata  as  a  larger  division 
including  the  vertebrate  phylum  and  one  or  more  proto- 
chordate  phyla.  This  is  simpler  for  beginners  who  will 
not  soon  study  protochordates,  and  moreover  will  intro- 
duce no  confusion  if  the  protochordates  are  later  studied 
in  advanced  college  courses. 

347.  Fishes.  —  The  sword-fish  (p.  421  in  Applied 
Biology)  is  a  bony  fish  and  has  no  close  relationship  to 
the  saw-fish  shark  and  saw-fish  ray. 

352.  Fossil  reptiles.  —  Page  427,  second  paragraph. 
Among  long  fossil  reptiles  that  have  been  discovered,  the 
Brontosaur  in  the  American  Museum  of  Natural  History 
in  New  York  is  66  feet  long,  the  Diplodocus  in  the 
Pittsburgh  Museum  is  over  80,  and  dinosaurs  recently 
found  in  Africa  are  over  100  feet. 

71 


72  TEACHERS'  MANUAL  OF  nioL'><  v 

354-358.  Birds.  —  Lantern  slides  for  lectures  on  birds 
are  sold  by  the  National  Association  of  Audubon  Socie- 
ties, 141  Broadway,  New  York  City.  Prices  per  slide, 
30  cents  plain  and  70  cents  colored.  A  list  of  more  than 
two  hundred  slides  will  be  sent  on  application.  The  same 
Association  publishes  excellent  pictures  of  birds  and 
leaflets  for  the  use  of  teachers. 

References :  Probably  the  most  useful  book  on  struc- 
ture and  functions  of  birds  is  Beebe's  The  Bird :  Its  Form 
and  Function  (Holt,  1906,  $3.50).  See  list  of  standard 
books  on  birds  cited  by  Bigelow,  1904,  p.  438.  Also  Bee 
Appendix  of  Holtz's  Nature  Study.  Important  books  pub- 
lished since  1904  are:  Hoffman's  Birds  of  New  England 
and  Eastern  New  York  (Houghton,  Mifflin,  $1.50) ;  Traf- 
ton's  Methods  of  Attracting  Birds  (Houghton,  1910,  $1.20) ; 
Knowlton  and  Ridgway's  Birds  of  the  World  (Holt,  1909, 
873  pp.,  ill.,  $7).  See  also  §  358  in  this  book. 

356.  "The  alimentary  canal  is  essentially  the  same  in 
all  birds."  This  refers  to  the  general  plan  of  structure, 
which  has  been  variously  modified  in  adaptation  to  food 
habits.  (See  Beebe,  The  Bird.) 

358.  Economic  Relations  of  Birds.  —  This  topic  was 
omitted  from  the  Applied  Biology  by  an  oversight  in  the 
last  revision  of  the  manuscript,  and  not  because  the  authors 
regarded  it  as  unimportant.  Teachers  should  call  the 
attention  of  students  (1)  to  the  enormous  value  of  the 
domesticated  birds  for  feathers,  meat,  and  eggs ;  (2)  to  the 
usefulness  of  the  insectivorous  birds  in  helping  to  keep 
injurious  insects  in  check ;  (3)  to  the  hawks  and  owls  that 
destroy  rodents ;  and  (4)  to  the  aesthetic  value  of  birds, 
because  of  their  singing,  beautiful  plumage,  and  interest- 
ing habits.  For  this  last  reason  alone  most  wild  birds  are 
well  worth  protection.  The  harmful  habits  of  certain 
birds,  notably  the  English  sparrow,  are  well  known. 
Weed  and  Dearborn's  Birds  in  Relation  to  Man  (Lippin- 


VERTEBRATES  73 

cott)  is  the  most  complete  summary  of  the  economic 
aspect  of  birds;  but  numerous  pamphlets  of  the  United 
States  Department  of  Agriculture,  Chapter  I  in  Chap- 
man's Bird  Life,  and  chapters  in  many  other  books  on 
birds  discuss  their  economic  relations.  Other  references : 
" Common  Birds  and  Agriculture"  (Farmers1  Bulletin 5 4) 
Educational  Leaflets,  published  by  National  Association  of 
Audubon  Societies,  New  York  City ;  Weed's  Farm  Friends 
and  Foes,  Part  IV  (Heath) ;  "  Economic  Value  of  Preda- 
ceous  Birds"  (Yearbook  Separate  474,  1908). 

359-362.  Mammals.  —  Hornaday's  American  Natural 
History  (Scribner's,  $3.50),  while  dealing  with  all  kinds  of 
vertebrates,  is  especially  good  on  mammals. 

360.  One  human  species  (Homo  sapiens)  is  mentioned 
on  p.  437  in  the  Applied  Biology.  Some  anthropologists 
classify  some  prehistoric  skulls  as  belonging  to  another 
species  (Osborn,  Age  of  Mammals). 

362.  Economic  mammals.  —  Reference  :  Weed's  Farm 
Friends  and  Foes,  Part  V  (Heath).  The  United  States 
Department  of  Agriculture  issues  many  pamphlets  on  farm 
mammals.  Also,  "Rabbits"  (Yearbook  Reprint  452,  1907)  ; 
" Economic  Value  of  Predaceous  Birds  and  Mammals" 
(Yearbook  Reprint  474) ',  " Danger  of  Introducing  Noxious 
Animals"  (Yearbook  Reprint  132,  1908);  and  others 
(see  Circular  19,  Div.  of  Pub.,  Publications  Classified  for 
Teachers.  Standard  books  on  mammals  are  cited  by 
Bigelow,  1904,  pp.  428,  439. 

363-365.  Life-histories  and  sex-instruction.  —  The  text 
of  the  Applied  Biology  presents  the  life-histories  of  verte- 
brates more  extensively  than  is  done  in  other  books  for 
high  schools,  because  the  authors  are  convinced  that 
biology  is  the  only  logical  approach  to  the  kind  of  sex- 
instruction  that  is  now  generally  recognized  as  an  im- 
portant part  of  education. 

If  the  Applied  Biology  is  studied  continuously  from 


74  TEACHERS'   MANUAL   OF  BIOLOGY 

Chapter  I,  then  the  students  will  have  met  the  great 
facts  of  reproduction  in  parts  of  the  following  sections : 
21,  22  (frog);  36  (sex-organs  of  frog);  56-63  (frog  de- 
velopment) ;  27,  28  (plant) ;  74-81  (reproduction  of  bean 
plant) ;  196-211  (reproduction  of  seed-plants) ;  122  (com- 
parison of  animals  and  plants) ;  224-226  (fern) ;  232 
(moss);  237-239  (simple  plants);  244  (molds);  251 
(yeast);  256  (bacteria);  267  (Paramecium) ;  270 
(Amoeba) ;  274  (malarial  organism) ;  279  (Volvox) ;  281 
(sponges);  283  (Hydra);  287,  288  (hydroids) ;  290 
(Scyphomedusae) ;  295  (tape-worm) ;  297  (Trichinae) ;  299 
(spontaneous  generation) ;  301  (sand  worm) ;  303  (earth- 
worm) ;  309  (p.  363)  and  310  (crayfish) ;  316  (barnacles) ; 
§  325  (insects);  §  337  (clams);  and  finally  363-367 
(vertebrates). 

In  high  schools  that  are  already  taking  advanced 
ground  in  that  they  are  making  their  course  of  general 
biology  apply  to  human  life  in  the  broadest  possible  way, 
there  could  be  no  more  natural  and  scientific  approach 
to  the  problems  of  human  life-history  than  a  review  of  the 
facts  of  reproduction  in  the  order  stated  above.  Per- 
haps it  might  seem  to  many  teachers  best  to  reverse  the 
order.  In  that  case,  start  a  review  with  yeast,  bacteria, 
and  other  simple  plants;  and  then  molds,  moss,  fern, 
bean,  and  other  seed-plants.  Likewise,  review  reproduc- 
tion of  one-celled  animals,  Hydra,  " worms,"  crusta- 
ceans, insects,  and  other  invertebrates;  and  finally  take 
up  §§  363-367  on  reproduction  of  vertebrates. 

Such  a  review,  culminating  in  the  highest  animals, 
will  marshal  the  great  facts  of  reproduction ;  and  in  the 
hands  of  a  competent  teacher  will  bring  students  to  a 
serious  and  open-minded  attitude  which  makes  human 
life-history  a  natural  culmination  of  biological  study. 

Just  how  much  of  the  facts  from  human  life  should 
supplement  such  studies  as  §§  363-367  is  still  a  matter  of 


VERTEBRATES  75 

discussion,  but  that  considerable  supplementing  is  now 
desirable  is  believed  by  the  authors.  The  point  of  view 
quoted  with  approval  by  Bigelow,  1904,  p.  285,  is  no 
longer  tenable.  Nothing  is  clearer  than  that  it  is  in- 
adequate to  leave  students  to  make  their  own  application 
of  biological  ideas  to  human  life.  The  demonstrated 
fact  is  that  most  of  them  do  not,  and  so  we  need  definite 
and  applied  teaching. 

On  a  few  points  only  do  the  authors  of  the  Applied 
Biology  feel  confident  as  to  the  desirable  work  supple- 
mentary to  biology  in  the  line  of  sex-instruction : 

(1)  Co-educational  college  classes  have  often  carried 
embryological  study  as  far  as  outlined  by  §  367  in  the 
Applied  Biology;  but  for  co-educational  high  schools  it 
seems  best  that  only  teachers  who  have  the  rather  rare 
ability  to  make  their  students  feel  that  all  biological  facts 
are   very   serious,    should    attempt   more   than   assigned 
reading  of  §  367.     If  a  review  of  §  367  is  made  in  class- 
work,  it  is  better  in  the  form  of  a  straightforward  lecture 
and  not  as  an  oral  recitation.     Of  course  no  sudden  change 
of  method  should  be  made  for  §§  363-367  that  will  attract 
the  attention  of  the  students;    it  is  certainly  wiser  to 
modify  methods  earlier  in  the  course.     One  way  of  doing 
this  is  to  assign  sections  for  reading  from  time  to  time, 
and  seemingly  not  to  find  time  for  recitations  on  them, 
or  to  lecture  occasionally  instead  of  holding  an  expected 
recitation. 

(2)  If  the  desirable  instruction  supplementary  to  §  367 
and  directly  applied  to  human  life  is  approved  by  the 
school  authorities,  separate  classes  for  students  of  each 
sex  are  obviously  necessary  in  either  high  school  or  general 
college.     Here  again  in  co-educational  schools  it  is  desir- 
able that  the  attention  of  students  should  not  be  attracted 
by  a  radical  change,  such  as  a  sudden  division  of  a  class, 
which  would  suggest  to  students  that  even  biology  dares 


7f>  TEACHERS'    .VM.vr.17,    OF  J1IOLOGY 

not  frankly  touch  the  problems  of  human  life.  It  is 
better  for  the  desirable  division  of  a  mixed  class  to  be 
made  on  some  reasonable  pretext,  such  as  the  convenience 
of  smaller  groups  for  a  promised  review,  which  only  the 
teacher  knows  is  planned  to  lead  up  to  human  life-history. 
Tact  and  skill  may  enable  the  teacher  to  carry  over  to 
human  life  that  attitude  of  frankness  and  open-mindedness 
which  biology  properly  taught  almost  always  develops  in 
students. 

Of  course,  the  advanced  student  of  human  life  must 
know  that  biological  study  soon  comes  face  to  face  with 
some  very  difficult  problems  in  connection  with  human 
life-history;  but  it  is  unfortunate  for  young  people  to 
have  this  impressed  upon  them  before  they  have  learned 
the  deeper  ethical  and  social  reasons  why,  in  general, 
there  should  be  maintained  a  certain  amount  of  reserve 
between  the  sexes  in  the  consideration  of  some  important 
problems  of  life.  No  educational  theory  or  practice  can 
possibly  alter  some  fundamental  aspects  of  human  life : 
among  them  the  psychical  and  physical  relations  of  the 
sexes  which  nature  has  fixed  immutably.  Therefore,  in 
presenting  applied  biological  study  as  a  part  of  general 
education,  teachers  do  well  to  pause  at  the  threshold  of 
human  life-history  and  recognize  that  there  are  good  and 
sufficient  reasons  why  very  many  important  biological 
facts  relating  to  reproduction  should  be  frankly  presented 
only  to  young  people  grouped  in  classes  limited  to  one  sex. 
This  proposition  seems  as  scientifically  certain  as  the 
rotation  of  the  earth. 

(3)  The  third  point  that  seems  to  the  authors  to  be  an 
established  guide-post  on  the  still  incomplete  pathway 
of  sex-education  is  that  the  prominent  biological  facts 
of  anatomy,  physiology,  embryology,  and  hygiene  applied 
to  human  reproduction  should  be  taught  as  supplementary 
to  §  367,  but  only  by  excellent  teachers.  Just  what  this 


VERTEBRATES  77 

means  in  detail  is  a  problem  on  which  the  American  Fed- 
eration for  Sex  Hygiene  will  probably  make  some  authori- 
tative announcement  within  a  year;  and  the  authors  of 
the  Applied  Biology  hope  to  complete  for  publication  a 
manuscript  that  will  suggest  their  views  in  detail  as  to 
how  §  367  should  be  expanded  and  supplemented. 

(4)  The  fourth  point  on  which  the  authors  of  the  Applied 
Biology  are  convinced  is  that  sex-education  will  be  inade- 
quate until  we  know  how  to  extend  it  safely  and  scien- 
tifically beyond  the  field  of  biology  into  ethics,  sociology, 
psychology,  and  aesthetics.  However,  this  fact  does  not 
interfere  with  the  work  of  the  teacher  of  biology,  for 
there  is  no  question  that  the  study  of  life-histories  of 
animals  and  plants  is  the  only  way  for  giving  students 
that  outlook  and  attitude  of  mind  that  is  absolutely 
necessary  for  proper  understanding  of  some  of  the  most 
complicated  problems  of  human  life;  and  it  is  the  only 
study  that  gives  the  fundamental  knowledge  of  structure 
and  function  of  reproductive  organs,  which  must  be 
understood  before  the  individual  can  appreciate  the  prob- 
lems of  sex-instruction  with  reference  to  human  life. 
Hence,  far  from  being  discouraged  because  biology  alone 
is  inadequate,  the  teacher,  on  the  contrary,  should  find 
stimulation  in  the  fact  that  biology  is  the  only  scientific 
approach  to  the  greatest  questions  involved  in  human 
life,  and  therefore  the  teacher  of  the  science  is  working 
on  the  foundations  on  which,  before  many  years  pass,  we 
may  know  how  to  build  a  satisfactory  scheme  of  sex- 
education.  The  most  practicable  step  now  possible  in 
the  world-wide  movement  for  sex-education  is  the  develop- 
ment of  the  full  possibilities,  of  the  biological  studies  that 
touch  the  problems  of  reproduction.  (Abstract  of  article 
by  M.  A.  Bigelow,  in  Journal  of  Social  Diseases,  October, 
1912.) 


78  TEACHERS1   MANUAL   OF  BIOLOGY 

References  Relating  to  Sex-instruction 

NOTE.  —  This  selected  list  contains  the  books  and 
articles  most  used  by  advanced  students  working  with 
the  author.  A  comprehensive  work  on  sex-education  now 
being  prepared  under  the  advice  of  a  committee  of  the 
American  Federation  for  Sex  Hygiene  (New  York,  105 
W.  40th  St.)  will  contain  a  more  extensive  bibliography. 

American    Society   of    Sanitary  and  Moral    Prophylaxis    (105 

West  40th  St.,  New  York  City)  publishes  six  Educational 

Pamphlets : 

No.  1 :   The  Young  Man's  Problem.     Pp.  32.     10  cents. 
No.  2 :   Instruction  in  the  Physiology  and  Hygiene  of  Sex.    Pp. 

24.     10  cents. 
No.  3:    The  Relations  of  Social  Diseases  with  Marriage  and 

Their  Prophylaxis.    Pp.  72.     25  cents. 
No.  4  :   The  Boy  Problem.    Pp.  32.     10  cents. 
No.  5:    How  My  Uncle,  the  Doctor,  Instructed  Me  in  Matters 

of  Sex.    Pp.  32.     10  cents. 

No.  6 :  Health  and  Hygiene  of  Sex.    Pp.  32.     10  cents. 
Journal  of  Social  Diseases.     Quarterly,  $1.00  per  year. 
BIQELOW,  M.  A.,  "Relation  of  Biology  to  Sex-instruction  in 

Schools   and   Colleges,"    Jour,   of  Social   Diseases,   II,   4, 

October,  1911. 
CABOT,  R.  C.,  Consecration  of  the  Affections.     (Often  Misnamed 

Sex-Hygiene.)     Proc.  of  Fifth  Congress  of  Amer.   School 

Hygiene  Assoc.,  Ill,  1911,  p.  114. 
EDDY,  WALTER  H.,  "An  Experiment  in  Teaching  Sex-Hygiene." 

Jour,  of  Educ.  Psychology,  II,  8,  October,  1911,  p.  440. 
ELIOT,  C.  W.,  School  Instruction  in  Sex  Hygiene.     Proc.  of  Fifth 

Congress  of  Amer.  School  Hygiene  Assoc.,  New  York,  1911, 

pp.  22-26. 
GALBRAITH,  ANNA,  Four  Epochs  of  a  Woman's  Life.     Saunders, 

$1.50.     (For  mature  women,  especially  mothers.) 
HALL,  G.  S.,  Adolescence.     Appleton,  2  vols.,  I,  Ap.  469,  507- 

512.     $7.50.     (For  parents  and  teachers.) 
HALL,  G.  S.,  "  Needs  and  Methods  of  Educating  Young  People  in 

Hygiene  of  Sex."     Pedagogical  Seminary,  15  :  82-91,  March, 

1908. 
HALL,  G.  S.,  "  Teaching  of  Sex  in  Schools  and  Colleges."     Jour. 

of  Social  Diseases,  II,  4,  October,  1911, 


VERTEBRATES  79 

HALL,  JE ANNETTE,  W.,  Life's  Story:  A  Book  on  a  Biological 
Basis  for  Girls  of  10  to  17.  B.  S.  Steadwell,  La  Crosse, 
Wis.;  $.25. 

HALL,  W.  S.,  Developing  into  Manhood:  A  Brief  Book  on  a  Bio- 
logical Basis  for  Boys  of  15  to  18.  Association  Press,  New 
York  City,  $.25. 

HALL,  W.  S.,  From  Youth  into  Manhood.  For  Young  Men  and 
Older  Boys.  Association  Press,  New  York  City.  $.50. 

HALL,  W.  S.,  Instead  of  Wild  Oats:  A  Brief  Book  for  Young 
Men  on  a  Biological  and  Sociological  Basis.  Revell  &  Co. 

HALL,  W.  S.,  Reproduction  and  Sexual  Hygiene.  Wynnewood 
Pub.  Co.,  Chicago.  Pp.  150.  $1.00.  (For  young  men  and 
fathers.) 

HALL,  W.  S.,  "Social  Hygiene:  Its  Pedagogic  Aspects  and  Its 
Relation  to  General  Hygiene  and  Public  Health."  Nature- 
Study  Review,  VI,  pp.  33-39,  February,  1910. 

HALL,  W.  S.,  "  The  Teaching  of  Sexual  Hygiene  :  Matter  and 
Methods."  School  Science  and  Mathematics,  X,  pp.  469-474, 
June,  1910. 

HENDERSON,  C.  R.,  Education  with  Reference  to  Sex.  I,  pp.  75, 
$.78  postpaid ;  II,  pp.  100,  $.80  postpaid.  University  of 
Chicago  Press. 

LOWRY,  E.  B.,  Truths:  Talks  with  a  Boy  ($.50);  Confidences: 
Talks  with  a  Young  Girl  ($.50) ;  Herself:  Talks  with  Women 
($1.10).  Forbes,  Chicago. 

MARTIN,  H.  N.,  Human  Body,  Advanced  Course,  Holt,  1910. 
(Last  chap,  in  any  edition,  but  especially  in  Ninth,  1910, 
is  excellent  general  account  of  anatomy,  physiology,  and 
hygiene  of  reproduction.) 

MORLEY,  MARGARET  W.,  "Teaching  Renewal  of  Life  in  Nature- 
Study."  Nature-Study  Review,  November,  1907. 

MORROW,  PRINCE  A.,  "Teaching  of  Sex-Hygiene."  Good  House- 
keeping, March,  1912.  Also  pamphlets  of  the  Society  for 
Prophylaxis,  see  above. 

MORROW,  PRINCE,  Social  Diseases  and  Marriage,  Lea  Bros.  1909. 

PARKINSON,  W.  D.,  "Sex  and  Education."  Educational  Review, 
41,  January,  1911;  pp.  42-59.  (Stands  for  ethical  and 
aesthetic  teaching.) 

SALEEBY,  C.  W.,  Parenthood  and  Race  Culture.  Moffat,  Yard 
&  Co.  1909.  (Popular  account  of  eugenics.) 

WILLSON,  R.  N.,  The  American  Boy  and  the  Social  Evil. 
Winston  Co.,  1909.  $1.00.  "Nobility  of  Boyhood,",  ex- 
tract, $.50.  For  high-school  boys. 


80  TEACHERS'  MANUAL  OF  BIOLOGY 

WOOD-ALLEN,  MAY.     What   a    Young   Woman    Should    Know. 

VlrPub.  Co.    $1.00. 

Also  see  §  491  in  this  Manual  for  books  on  heredity  and 
eugenics. 

367.  It  would  be  interesting  to  add  to  the  legend  of 
Fig.  154  that  the  embryo  and  all  surrounding  membranes 
shown  developed  from  the  fertilized  egg-cell.  There  are 
thousands  of  cells  in  the  stage  represented. 

369.  Regarding  the  species  of  Homo,  see  note  in  §  360 
in  this  Manual. 


CHAPTER  XVII 
HUMAN  ANATOMY  AND  PHYSIOLOGY 

370-490.  Order  of  study.  —  This  chapter  on  human 
structure  and  life-activities  and  the  following  chapter, 
which  is  largely  hygienic,  are  preferably  studied  after 
Parts  I,  II,  and  III ;  but  may  be  studied  after  Chapters 
I,  II,  III,  and  IV  in  order  to  make  a  short  course  that 
centers  in  human  physiology.  Still  another  possible 
arrangement  for  a  very  short  course  in  the  study  of  the 
human  body  is  to  start  with  §§  370-373,  then  turn  to 
§§  38-41  and  study  tissues  and  cells,  then  §§  42-55,  which 
apply  to  the  human  body  as  well  as  to  the  frog.  Sub- 
stitute "human  body"  wherever  the  word  "frog"  occurs 
in  §§  42-55  (except  in  paragraph  on  heat  on  p.  52  and 
in  references  to  respiration  as  done  in  part  by  frog's  skin). 
Next  study  §§  375-524.  Finally  study  Chapter  XVIII. 

In  either  of  the  above  plans  for  a  brief  course  on  hu- 
man biology,  the  public  hygiene  part  of  Chapter  XVIII 
ought  to  be  introduced  by  study  of  bacteria  (§§  254-265). 

Human  and  general  biology.  —  On  the  educational  rela- 
tions of  these  two  aspects  of  biology,  see  Bigelow,  1904, 
pp.  457-465.  On  relation  of  human  aspect  of  biology  to 
nature-study,  see  Nature-Study  Review,  Vol.  II,  pp.  67- 
72,  February,  1906. 

Emphasizing  principles.  —  The  authors  of  the  Applied 
Biology  are  aware  of  much  repetition  in  Chapter  XVII 
of  facts,  especially  physiological,  stated  in  earlier  chap- 
ters ;  but  this  has  been  deliberate  and  after  due  considera- 
tion leading  to  the  conclusion  that  the  great  principles  of 
G  81 


82  TEACHERS'  MANUAL   OF  BIOLOGY 

biology  must  be  repeated  again  and  again  from  different 
points  of  view  before  they  will  become  an  integral  part 
of  the  life  and  thought  of  the  student.  We  cannot  too 
often  emphasize  the  statement  that  teachers  of  biology 
should  aim  to  familiarize  the  student  with  the  great 
ideas  of  the  science.  Certainly,  familiarity  does  not 
often  come  from  one  momentary  contact  with  things 
worth  knowing  in  any  field  of  knowledge.  A  further 
justification  for  repetition  in  this  chapter  is  that  here  we 
are  concerned  with  applying  the  great  principles  of  biology 
to  the  human  species. 

Books  Supplementary  to  this  Chapter 

For  students :  Eddy's  General  Physiology;  Peabody's 
Studies  of  Physiology;  Martin's  Human  Body,  Briefer 
Course;  and  other  standard  high-school  text-books  of 
physiology. 

For  teachers :  Hough  and  Sedgwick's  Human  Mechanism  ; 
Huxley  and  Lee's  Lessons  in  Physiology;  Martin's  Human 
Body,  Advanced  Course  (1910  edition) ;  Howell's  Text- 
book of  Physiology;  and  Halliburton's  Handbook  of 
Physiology.  See  also  appendix  to  this  Manual. 

370.  Anterior,  posterior,  dorsal,  and  ventral  should  be 
applied  as  in  the  case  of  the  frog  (p.  26,  Applied  Biology). 
Anterior  for  ventral  and  posterior  for  dorsal  in  the  older 
non-comparative  human  anatomy  should  not  be  used  to 
confuse  young  students.  The  words  anterior  and  posterior 
should  be  erased  in  description  of  Fig.  162,  p.  512.  More 
advanced  students  must  also  learn  the  older  usage,  which 
is  still  found  in  many  text-books. 

Selection  of  subject-matter.  —  The  selection  of  facts  for 
Chapters  17  and  18  in  the  Applied  Biology  is  largely  in 
harmony  with  the  principles  stated  by  Bigelow,  1904,  pp. 
465-472.  The  authors  would  advise  schools  to  supple- 


HUMAN  ANATOMY  AND  PHYSIOLOGY  83 

ment  many  points,  especially  by  experiments  gleaned  from 
standard  text-books  of  elementary  physiology  and  hygiene. 
Teaching  -hygiene.  We  are  now  in  a  period  of  such 
rapid  improvement  of  hygienic  teaching,  especially  in  the 
advanced  nature-study  and  introduction  to  science  in 
grammar  grades  and  first  year  of  high  schools,  that  soon 
the  time  will  come  when  only  an  outline  of  the  biological 
relations  of  human  life  and  other  life  will  be  needed  in 
a  course  of  applied  biology.  Hence  it  has  seemed  best 
to  the  authors  to  anticipate  somewhat  the  culmination 
of  this  movement  towards  efficient  hygiene  teaching,  and 
so  they  have  omitted  from  the  Applied  Biology  numerous 
elementary  facts  that  belong  in  school  years  earlier  than 
those  for  which  that  book  is  intended. 

373.  Human  structure.  —  It  is  desirable  to  supplement 
the  text  by  blackboard  diagrams  showing  that  the  dia- 
phragm divides  the  body-cavity  into  two,  (1)  the  thoracic 
cavity  with  heart  and  lungs  and  (2)  the  abdominal  cavity 
with  the  stomach,  intestines,  liver,  kidneys,  etc.     Em- 
phasize the  fact  that  there  are  in  the  human  body  the 
same  organs  as  in  the  frog,  in  the  same  relative  positions, 
but  that  detailed  study  would  show  the  human  organs  to 
be  more  complicated  in  structure.     Emphasize  the  re- 
markable similarity  of  the  general  human  structure  to 
that  of  the  frog,  and  indeed  of  all  vertebrates. 

374.  Cells.  —  Emphasize  the  statement  that  life-activ- 
ities are  in  living  cells  in  all  parts  of  the  body  and  not 
simply  in  the  brain,  heart,  and  lungs,  as  was  once  supposed. 
Injury  to  any  of  these  three  organs  may  soon  result  in 
death,  because  of  interference  with  the  functions  that 
serve  the  cells  (see  Applied  Biology,  §  436). 

375.  Foods.  —  It  is  not  to  be  expected  that  students 
will  do  more  than  make  a  list  of  common  animal  and  plant 
foods.     Grouping    according    to    constituent    food-prin- 
ciples is  included  in  §§  378-381. 


84  TEACHE11S    MANUAL   OF  BIOLOGY 

376.  Nutrients.  —  Instead  of  this  term  some  teachers 
prefer  the  term  "food-compounds." 

377.  It  seems  best  to  introduce  the  chemistry  of  foods 
at  this  point  instead  of  in  the  introductory  chemical  work 
in  Chapter  II ;  but  on  this  matter  authors  disagree.     See 
recent  high-school  books  by  Hunter  (A.  B.  Co.),   Peabody 
and  Hunt  (Macmillan),  Payne  (A.  B.  Co.),  Sharpe  (A.  B. 
Co.). 

377.  Fehling's    reagent    for    certain    sugars     (lactose, 
maltose,  glucoses)  may  be  purchased  from  chemists  and 
kept  in  two  bottles  ready  for  mixing  when  needed.     Solu- 
tion A:    copper  sulphate,  35  grams  in  200  cc.  of  water. 
Solution  B:   48  grams  of  caustic  soda  (NaOH)  and  173 
grams  of  Rochelle  salt  (sodium   potassium   tartrate)    in 
480  cc..  of  water.     When  needed,  mix  \  a  test-tube  of  B 
with  J  a  tube  of  A  and  \  a  tube  of  water.     Heat  some 
of  this  mixture  (blue  in  color)  to  boiling,  and  add  the  sup- 
posed sugar  solution  drop  by  drop.     Red  colored  pre- 
cipitate, especially  after  standing  and  cooling,  indicates 
a  reducing  sugar,  usually  glucose  in  plant  materials ;  but 
other  tests  are  necessary  to  distinguish  accurately  the  kind 
of  sugar.     Cane  sugar  (from  beet,  cane,  or  maple)  does 
not  give  the  red  color. 

For  a  simple  test,  make  solution  A  as  above  and  instead 
of  B  use  a  strong  solution  of  caustic  soda  or  potash.  Mix 
and  heat  as  directed  for  Fehling's  test. 

Eimer  and  Amend,  New  York,  and  doubtless  other 
chemical  supply  companies,  sell  tablets  for  Fehling's 
solution.  Price  20  cents  per  set  of  three  vials  of  25  tablets 
each. 

Nitric  acid  test.  —  Cool  test-tube  before  adding  ammonia 
(p.  462  in  Applied  Biology). 

378.  Carbohydrates.  —  The  formula  for  starch,  dextrin 
and  vegetable   gums    is    (CeHioOs)^..     Glycogen   (animal 
starch)  found  in  animal  tissues  (especially  livers)  should 


HUMAN  ANATOMY  AND  PHYSIOLOGY  85 

also  be  mentioned  as  a  carbohydrate  food.     Cane-sugar 
is  also  called  saccharose  or  sucrose. 

379.  Digestible  fats  (e.g.,  in  meat)  and  oils  (e.g.,  olive 
oil)  are  all  liquid  when  they  reach  the  intestine.  Many 
old  text-books  called  the  fats  "  hydrocarbons ";  but 
chemists  now  use  this  term  for  compounds  of  C  and  H ; 
e.g.,  benzine,  naphtha,  paraffin,  and  gasoline  are  mixtures 
of  such  compounds.  The  fats  occurring  in  animals  and 
plants  are  compounds  of  C,  H,  and  O ;  i.e.,  they  are  oxygen 
derivatives  of  hydrocarbons. 

381.  Albuminoids  are  so  closely  related  to  the  typical 
albumins  that  they  are  now  included  among  the  proteins, 
under  the  name  of  sclero-proteins.     Gelatin  is  digested 
like  ordinary  proteins.     The  one  striking  difference  be- 
tween albuminoids  and  the  ordinary  proteins  is  the  absence 
of  tyrosine  and  tryptophane,  two  amino-acids  which  enter 
into    the    composition    of    common    proteins.     Recent 
experiments  have  shown  that  by  adding  these  to  gelatin  it 
may  be  made  to  take  the  place  of  ordinary  protein  food. 
However,  for    practical  purposes  gelatin,  like  fats  and 
carbohydrates,  must  be  used  in  mixed  diet  with  the  ordi- 
nary proteins  obtainable  from  animal  and  plant  tissues. 

382.  Elements  in  human  body.  —  Examples  of  inorganic 
materials   in   the   human   body   are    calcium   phosphate 
(abundant  in  bones  and  teeth),  potassium  and  sodium 
phosphates  in  blood  and  tissues,   calcium  carbonate  in 
bones  and  teeth,  potassium  and  sodium  carbonates  and 
sulphates  in  blood  and  tissues,  iron  in  haemoglobin  of  the 
blood.     The     fourteen     elements     that    appear     to    be 
essential  in  the  composition  of  the  human  body  are  as 
follows,  and  the  figures  in  parentheses  indicate  percent- 
ages :  O  (72),  C  (13.5),  H  (9.1),  N  (2.5),  Ca  (1.3),  P  (1.15) ; 
and  the  following  are  less  than  one  per  cent  and  important 
in  the  order  stated  :  S,  Na,  Cl  Fl,  K,  Fe,  Mg,  Si.  Note  that 
over  97  per  cent  is  composed  of  four  elements,  C,  H,  N,  0. 


Si)  TEACHERS'  MANUAL   OF  BIOLOGY 

388.  Epithelial  cells  from  the  lining  of  the  mouth  may 
be  obtained  by  gently  scraping  inside  a  cheek  with  a  tooth- 
pick or  flat  piece  of  wood,  and  mounting  the  scrapings  in 
a  drop  of  water  on  an  object-slide.  Stain  with  iodine- 
eosin,  or  other  anilin  stains. 

392.  Intestine.  —  A  detailed  description  of  the  small 
intestine  seems  unnecessary,  but  duodenum  as  the  name 
of  the  part  nearest  the  stomach  might  be  introduced. 
Charts,  manikins,  illustrations  in  books,  and  blackboard 
diagrams  will  be  useful  in  this  and  the  two  following 
sections. 

396.  Digestive    movements.  —  Hough    and    Sedgwick's 
Human  Mechanism  contains  diagrams  illustrating  mus- 
cular constrictions  of  the   stomach   and  small  intestine. 

397.  Digestion  of   sugar.  —  Only  sugar  of    the    grape 
sugar  formula  (CeHiaOe)  is  absorbed  abundantly  without 
digestion.     Cane  sugar  is  digested  in  the  intestine  from 
•CuHaOu  to  C6H]206. 

398.  Osmosis.  —  For  making  apparatus  for  osmosis  of 
digested  foods,  "gold-beater  membranes  for  osmosis"  are 
sold  by  Eimer  and  Amend,  New  York,  at  about  $1  to  $1.50 
per  dozen.    Two  bags,  each  about  three  inches  long,  may 
be  made  from  each  by  carefully  folding  the  open  end,  tying 
with  coarse  thread,  and  then  cutting  the  bag  in  the  middle. 
When  water-soaked,  the  tied  end  will  not  leak.     Always 
soak  such  membranes  for  ten  minutes  before  using  and  test 
for  leaking  by  wiping  the  outside  dry  and  then  filling  with 
water.    See  also  §  88  in  this  Manual. 

A  simple  osmose-apparatus  for  use  with  this  and  similar 
experiments  may  be  made  as  follows :  Cut  (with  edge 
of  a  file)  pieces  of  glass  tubing  about  f  of  an  inch  in  diameter 
and  three  inches  long.  Heat  one  end  of  each  piece  until 
the  glass  is  softened,  and  then  press  against  a  flat  piece 
of  metal  so  as  to  form  a  collar  at  the  end  of  the  tube. 
Now  take  a  sheet  of  gold-beaters'  membrane,  parchment, 


HUMAN  ANATOMY  AND  PHYSIOLOGY  87 

or  bladder,  about  two  inches  in  diameter,  fold  it  into  bag 
form  and  tie  around  the  collar  of  the  glass  tube,  wrapping 
string  firmly  around  several  times  and  then  tying. 

The  tube  may  be  inserted  through  a  hole  in  a  piece  of  wood 
or  cork  which  will  form  a  convenient  support  over  a  small 
tumbler  or  bottle  containing  pure  water  into  which  the 
membrane  should  dip.  Let  the  membrane  soak  in  water 
fifteen  minutes  before  using.  Materials  to  be  tested  for 
osmosis  may  be  poured  into  the  tube  by  means  of  a  rubber- 
bulbed  pipette.  A  number  of  these  pieces  of  apparatus 
should  be  made.  If  washed  directly  after  using  and  then 
quickly  dried,  they  may  be  used  on  many  occasions  with- 
out changing  the  membranes.  Or  after  washing  they 
may  be  preserved  in  a  sealed  Mason  jar  containing  water 
with  a  teaspoonful  (5  cc.)  of  commercial  formalin  in  a  quart 
of  water.  Probably  a  trace  of  boric  acid,  carbolic  acid, 
or  other  antiseptic  would  preserve  the  membranes 
equally  well. 

416.  Energy.  —  Probably  the  best  elementary  account 
of  energy  transformations  in  relation  to  food  is  given  in 
Martin's  Human  Body,  Briefer  Course,  in  the  chapter 
on  "Why  we  Eat  and  Breathe."  Also  refer  students  to 
elementary  text-books  of  physics.  Clear  ideas  of  energy 
conservation,  storage,  and  transformation  are  essential 
to  an  understanding  of  even  the  elementary  problems  of 
human  nutrition,  and  hence  it  is  well  worth  while  at  this 
stage  to  digress  into  the  field  of  physics  far  enough  to 
present,  or  to  review,  the  chief  facts  concerning  energy 
that  physiology  needs. 

418.  Protein  oxidation.  —  The  availability  of  only  4 
calories  of  the  5.6  in  a  gram  of  protein  is  due  to  the  in,- 
complete  oxidation  of  that  food  in  the  living  body.  The 
nitrogenous  excretions  of  cells  are  compounds  of  C  H  0  N 
and  may  be  completely  oxidized  in  a  chemist's  bomb 
calorimeter.  On  the  other  hand,  the  fats  and  carbohy- 


88  TEACHERS'   MANUAL   OF  BIOLOGY 


drates  are  largely  oxidized  to  d\  and  HO2  in  tho  living 
cells. 

Oxidization  at  the  low  temperatures  of  living  cells  is 
probably  due  to  enzyme  action. 

Energy  value  of  food  of  farm  animals  is  given  in  Farmers1 
Bulletin  346. 

On  chemists'  methods  of  computing  energy  value  of 
foods,  see  "Bomb  Calorimetry"  (Bulletin  124,  Bureau  of 
Animal  Industry). 

419.  Respiration  calorimeter.  —  An   illustrated  descrip- 
tion of  a  calorimeter  for  human  use  is  in  Yearbook  Sepa- 
rate 539  (1910),  free. 

420.  Composition  of  typical  foods  is  given  in  the  ap- 
pendix of  Sherman's   Chemistry  of  Food  and  Nutrition 
(Macmillan,    1911,    $1.50),    an   excellent    handbook   for 
students  of  dietetics  and  food  economics,  and  also  on  the 
chemistry  of  digestion  and  metabolism.     See  the  same 
book  for  comparative  economy  of  foods,  ranging  from  8  cents 
per  3000  calories  in  wheat  flour  to  $1.13  for  eggs  at  35  cents 
per  dozen,  $1.26  for  lean  beefsteak,  and  $1.90  for  oysters. 

Some  interesting  studies  of  foods  and  dietaries  are  in 
Sharpens  Laboratory  Manual,  Problem  42. 

423.  Protein  diet.  —  A  working  man  would  require  720 
grams  of  protein  for  necessary  daily  energy  if  he  took  no 
food  but  lean  meat  (middle  of  p.  500  in  Applied  Biology). 

Growing  children  require  more  food  than  adults  in  pro- 
portion to  weight.  Some  practical  advice  and  references 
to  books  on  feeding  young  children  are  included  in  Techni- 
cal Education  Bulletin  No.  3  (10  cents),  Teachers  College, 
New  York  City. 

,  424.  Dietetics.  —  On  the  problem  of  quantity  of  foods 
required,  see  Sherman's  Chemistry  of  Food  and  Nutrition, 
New  York,  Macmillan,  1911,  $1.50.  A  brief  paper  by  the 
same  author  is  in  Technical  Education  Bulletin  No.  5 
(10  cents),  Teachers  College,  New  York  City. 


HUMAN  ANATOMY  AND   PHYSIOLOGY  89 

425.    Respiration.  —  See  §  51. 

429.  Air  in  lungs.  —  About  four  to  five  per  cent  of  the 
oxygen  of  the  air  is  absorbed  while  in  the  lungs,  and 
almost  as  much  carbon  dioxide  is  added. 

A  strong  adult  at  rest  passes  into  and  out  of  the  lungs 
nearly  650,000  cubic  inches  of  air  in  twenty-four  hours 
(30  cu.  in.  X  15  times  per  minute  X  60  minutes  per  hour 
X  24  hours  =  648,000  cu.  in.),  while  a  man  working  hard 
will  breathe  over  twice  this  amount. 

To  simplify  the  third  paragraph  in  this  section,  erase 
"  which  contain  ...  in  the  lungs."  Also,  200,  not  100 
cubic  inches  usually  remain  in  the  lungs  (last  sentence) ; 
only  100  after  forced  expiration. 

435.  Skin  in  excretion.  —  The  old  idea  that  the  skin 
is  an  essential  excretory  organ  is  largely  based  upon  the 
fact  that  death  once  resulted  from  varnishing  the  entire 
skin  and  covering  with  gold-leaf.  This  coating  was  sup- 
posed to  have  prevented  the  escape  of  some  very  poisonous 
excretions.  Later  studies  have  shown  that  metallic 
coverings  radiate  heat  rapidly  and  thus  cause  the  lowering 
of  the  internal  temperature  far  below  the  normal,  result- 
ing in  " freezing  to  death."  This  does  not  mean  0°  C.  or 
32°  F.,  for  a  rabbit  dies  from  low  temperature  if  its  in- 
ternal heat  is  reduced  below  about  70°  F.  No  human 
is  known  to  have  lived  after  reaching  an  internal  tem- 
perature below  80°  F.  The  skin  might  be  completely 
covered  with  a  varnish  so  as  to  close  all  pores  of  the  sweat- 
glands  and  no  harm  result,  provided  that  internal  tem- 
perature remained  normal.  In  short,  the  skin  is  a  heat- 
regulating  organ,  not  primarily  an  excretory  organ,  and 
there  is  no  reason  for  supposing  that  it  is  necessary  for 
eliminating  any  excretions  that  cannot  be  removed  by  the 
kidneys.  It  is  clear,  then,  that  excretion  of  water  by  the 
skin  occurs  only  as  a  means  for  heat  elimination. 

447.   Internal  heat.  —  The  importance  of  heat  regula- 


90  TEACHERS'   MANUAL   OF  BIOLOGY 

tion  may  be  further  illustrated  by  reference  to  "sun- 
stroke" or  "heat  prostration,"  due  chiefly  or  solely  to 
high  internal  temperature.  A  man  has  remained  eight 
minutes  in  dry  air  at  260°  F.,  but  the  activity  of  the  skin 
glands  prevented  internal  overheating.  An  internal 
temperature  above  104°  F.  means  serious  illness,  and 


CHAPTER  XVIII 
BIOLOGY  APPLIED  TO  HYGIENE 

448-462.  Personal  hygiene.  —  References :  Pyle's  Per- 
sonal Hygiene  (Saunders) ;  Part  II  of  Hough  and  Sedgwick's 
Human  Mechanism  (Ginn) ;  Allen's  Civics  and  Health 
(Ginn) .  All  are  adapted  to  advanced  high-school  students. 

For  young  students :  Ritchie's  Primer  of  Hygiene 
(World  Book  Co.) ;  Davison's  Health  Lessons  (American 
Book  Co.) ;  Gulick's  Hygiene  Series  (Ginn) ;  Hutchin- 
son's  Health  Series  (Houghton,  Mifflin). 

463-481.  Stimulants  and  Narcotics.  —  The  laws  of 
many  States  require  high  schools  to  give  instruction  con- 
cerning the  physiological  effects  of  alcohol,  tobacco,  tea, 
coffee,  and  drugs,  usually  in  the  first  year.  The  topic 
is  treated  in  the  Applied  Biology  in  accordance  with  laws 
in  the  States  where  the  book  may  be  used  by  teachers- 
in-training;  and  the  briefer  course  will  attempt  to  fit 
the  laws  relating  to  the  first  year  of  the  high  school. 
Obviously,  more  emphasis  is  given  than  would  be  de- 
manded by  its  fair  share  of  space  in  a  book  of  applied 
biology.  If  either  book  is  used  under  conditions  that  do 
not  make  such  instruction  mandatory,  as  in  private 
schools,  it  will  suffice  to  require  a  careful  reading  of  the 
paragraphs  463-481  and  to  give  a  recitation  including  the 
chief  points  such  as  are  summarised  in  §  478  and  479  of 
the  Applied  Biology  and  by  Bigelow,  1904,  p.  480.  The 
same  author  gives  (1904,  pp.  472-485)  a  bibliography  and 
summary  of  the  relation  of  temperance  instruction  to  high- 
school  biology.  There  has  been  no  notable  change  in 

91 


IVJ  TEACHSB&  MANUAL  OF  BIOLOGY 

the  situation  since  1904,  except  a  widesprra'i  tendency 
to  ignore  the  laws. 

On  the  educational  aspects  of  "temperance  instruction" 
see  Bigelow,  1904,  pp.  472-485.  Important  additions  to 
the  literature  list  there  given  are  :  F.  L.  Charles  in  Nature- 
Study  Review,  Vol.  IV,  Dec.,  1908,  pp.  287-292.  (Review 
of  movement  for  change  of  law  in  Illinois.)  "An  official 
Letter,"  Science,  Vol.  XXVI,  Oct.  4,  1907,  pp.  443-444. 
(Instructions  to  publishers  of  text-books.) 

Present  Knowledge.  Martin's  Human  Body,  Advanced 
Course,  Ninth  (1910)  edition,  pp.  393-395.  Howell'- 
Text-book  of  Physiology,  Third  (1909)  edition,  pp.  887-889, 
have  good  summaries  of  the  present  state  of  physiological 
knowledge  regarding  alcohol. 

466.  Effects  of  alcohol.  —  While  the  first  superficial 
effect  of  alcohol  appears  to  be  that  of  a  stimulant,  many 
authors  regard  it  as  really  a  narcotic,  even  in  small  do-- 
and  believe  that  its  apparent  stimulating  effect  is  due  to 
inhibition  or  depression  of  certain  control  centers  in  the 
nervous  system.  For  example,  it  is  claimed  by  some 
physiologists  that  alcohol  in  small  amounts  causes  rush 
of  blood  to  the  skin  because  it  depresses  the  nerve  center 
that  normally  controls  vaso-constriction  of  cutaneous 
arteries ;  and  likewise  it  increases  the  heart-beat  because 
it  depresses  the  center  (cardio-inhibitory)  that  keeps  the 
normal  heart  from  too  rapid  action.  It  leads  to  wit  and 
repartee  because  judgment  and  caution  are  inhibited. 
However,  as  a  practical  problem,  small  doses  of  alcohol 
result  in  certain  stimulative  effects,  no  matter  how  in- 
directly they  may  have  been  brought  about ;  and  so  far  as 
average  intelligent  readers  can  easily  observe  the  effects 
they  must  be  considered  stimulating  for  small  doses  and 
narcotic  for  large  ones.  But  this  does  not  alter  the  fact 
that  either  a  stimulant  or  a  narcotic  may  be  harmful  — 
that  is  another  problem. 


BIOLOGY  APPLIED   TO  HYGIENE  93 

467.  Alcohol  a  "poison."  —  The  authors  of  the  Applied 
Biology  are  acquainted  with  various  pharmacological 
literature  on  the  classification  of  alcohol  as  a  poison; 
but  although  they  would  gladly  accept  a  scientific  demon- 
stration of  the  truth  of  that  proposition,  they  are  still 
unconvinced  that  there  is  anything  to  be  gained  in  the 
line  of  temperance  by  publishing  for  lay  readers  the  state- 
ment that  alcohol  is  always  a  poison.  Whatever  may  be 
the  scientific  conception  of  a  poison,  teachers  of  science 
have  no  moral  right  to  overlook  the  popular  understand- 
ing of  the  word ;  hence  the  attitude  of  §  467  in  the  Applied 
Biology. 

481.  Drugs.  —  Harmful  effects  of  headache  powders 
(Chemistry  Bulletin  126,  U.  S.  Dept.  Agriculture,  free; 
also  Farmers'  Bulletin  377).  " Habit-Forming  Agents" 
(Farmers'  Bulletin  398). 

482-490.  Public  hygiene.  —  Reference  for  students : 
Conn's  Bacteria,  Yeasts,  and  Molds,  Chapters  XV,  XVI. 
Ritchie's  Primer  of  Sanitation  (World  Book  Co.,  Yonkers, 
N.Y.).  See  also  §§  448-462  in  this  Manual. 

References  for  teachers :  Part  II  of  Hough  and  Sedg- 
wick's  Human  Mechanism;  Sedgwick's  Sanitary  Science 
and  Public  Health;  Newman's  Bacteria  and  the  Public 
Health,  Allen's  Civics  and  Health. 

484.  Preventing  infection.  —  References:  "Typhoid" 
(Farmers' Bulletin  487) ;  " House  Flies"  (Farmers'  Bulletin 
459}.  Also  books  mentioned  above. 

489.  References:  "Some  Common  Disinfectants" 
(Farmers'  Bulletin  345).  Chapter  17  in  Conn's  Bacteria, 
Yeasts,  and  Molds  in  the  Home. 


CHAPTER -XIX 
EVOLUTION  AND  HEREDITY 

491.  For  discussion  of  educational  aspects  of  evolu- 
tion, see  Bigelow,  1904,  pp.  286-289.  For  list  of  literature, 
see  same  author,  pp.  429-432,  and  certain  books  named 
below.  The  following  books  published  since  1904  are 
important : 

Evolution 

CAMPBELL,  D.  H.     Plant  Life  and  Evolution.     New  York,  Holt. 

1911.     Pp.360.     $1.60.     (A  popular  historical-biographical 

account  of  biology  and  the  evolution  theory.) 
CRAMPTON,  H.  E.     Doctrine  of  Evolution.    New  York,  Columbia 

Univ.     Press.     1911.     Pp.    311.     $1.50.      (An     interesting 

series  of  lectures  in  popular  style.) 
GEDDES,  P.,  and  THOMSON,  J.  A.     Evolution.     London,  Williams. 

New    York,    Holt,     1911.     Pp.    256.     $.50.  "  (One  of    the 

most    readable    general    statements    of    evolution.     Good 
.  literature  list.) 
LOCY,  W.  A.     Biology  and  Its  Makers.    New  York,  Holt.     1908. 

Pp.  469,  123  figs.     $2.75. 
METCALF,  M.  M.     Outline  of  the  Theory  of  Organic  Evolution. 

New  York,  Macmillan.     1904.     Pp.  204,  101  pis.,  46  figs. 

$2.50. 
SCOTT,   D.   H.     The   Evolution   of  Plants.     London,  Williams; 

New  York,  Holt.     1911.     Pp.  256.     111.     $.50. 
THOMSON,   J.   A.      Darwinism    and   Human   Life.     New   York, 

Holt.     London,     Melrose.     1909.     Pp.     245.     $1.50.     (Six 

introductory  lectures  on  evolution.     Bibliography  excellent.) 
JORDAN,  D.  S.,  and  KELLOGG,  V.  L.     Evolution  and  Animal  Life. 

New   York,   Appleton.     1907.     Pp.   489,   3   pis.,  298  figs. 

$2.50. 
KELLOGG,  V.  L.     Darwinism  To-day.     New  York,  Holt.     1907. 

Pp.  403.     $2.00.      (Excellent  review  of  factors  of  evolution.) 
94 


EVOLUTION  AND  HEREDITY  95 

Heredity 

CASTLE,  W.  E.     Text-book  of  Heredity.    New  York,  Appleton. 

1911.     $1.50. 

DAVENPORT,  C.  B.     Eugenics.    New  York,  Holt.     1910.     $.50. 
DAVENPORT,   C.   B.     Heredity  in   Relation   to   Eugenics.     New 

York,  Holt.     1911.     $2.00. 

DONC ASTER,  L.     Heredity  in  the  Light  of  Recent  Research.     Cam- 
bridge University  Press.     New  York,  Putnams.     1911.     Pp. 

143.     $.40. 
KELLICOTT,  W.  E.     The  Social  Direction  of  Human  Evolution. 

New  York,  Appleton.     1911.     Pp.  249.     $1.50. 
PUNNETT,  R.  C.     Mendelism.     London  and  New  York.     1911. 

Pp.  192.     $.50. 
THOMSON,    J.    A.     Heredity.     London,    Murray.     New    York, 

Putnam.     1907.     Pp.  605,  49  figs.     $3.50. 
Also  an  excellent  chapter  in  Geddes  and  Thomson's  Evolution. 


APPENDIX  I 

DRAWINGS  AND  NOTES 

THE  authors  have  attempted  to  designate  in  the  Applied 
Biology  only  a  few  important  drawings  to  be  made  by  the 
pupils.  Most  teachers  will  probably  require  others.  Since  it 
is  a  question  whether  laboratory  study  of  biology  has  not,  in 
many  high  schools  and  colleges,  become  more  of  an  art  exercise 
than  a  scientific  study,  it  seems  best  to  require  only  drawings 
that  represent  structures  of  importance.  The  type  of  drawing 
best  adapted  to  high-school  biology  is  a  simple  line  drawing 
without  shading.  Time  spent  in  filling  in  details,  e.g.,  color 
spots  of  frog,  is  wasted  so  far  as  biology  for  general  education 
is  concerned,  because  in  most  cases  such  details  are  of  little  or 
no  significance  in  relation  to  the  great  ideas  of  the  science  that 
it  is  the  duty  of  the  teacher  and  book  to  emphasize.  Notes 
should  be  carefully  made  in  all  cases  where  record  of  laboratory 
work  cannot  be  made  in  drawings.  Clearly  written  and  logical 
paragraphs  should  be  required.  On  drawings  and  notes,  see 
Bigelow,  1904,  pp.  316-319;  and  Ganong,  1899,  Chapter  IV, 
or  1910,  Chapter  V,  89-108. 

Students  should  study  any  illustrations  in  books  which  will 
help  them  understand  structure.  Some  teachers  will  criticize 
this  recommendation  because  they  want  the  students  to  make 
original  drawings  and  diagrams,  a  plan  that  is  interesting  in 
theory,  but  of  very  little  significance  in  practice.  If  the  teacher 
is  chiefly  interested  in  guarding  against  direct  copying  from 
books,  then  loose-leaf  notebooks  should  be  adopted  and  the 
sheets  left  on  the  teacher's  desk  at  the  close  of  each  lesson. 
Of  course,  the  average  teacher  is  too  busy  to  correct  these  sheets 
carefully,  but  in  five  minutes  many  sheets  may  be  glanced  over 
and  marked  with  a  rubber  stamp  so  that  substitution  of  later 
work  is  impossible.  Do  not  pretend  to  correct  the  notes  at  the 
time  of  such  brief  examination,  but  simply  aim  to  inspect  and 
perhaps  grade  tentatively.  In  fact,  I  often  wonder  whether 
correction  of  mistakes  in  notes  should  not  be  done  chiefly  as  a 
H  97 


98  TEACHERS'  MANUAL  OF  BIOLOGY 

class  exorcise  in  which  students  cither  criticize  each  other's 
work  or  compare  their  own  notes  with  some  that  have  been 
selected  and  approved  by  the  teachers.  This  would  be  an  excel- 
lent experiment  for  a  teacher  with  several  sections  of  students 
taking  the  same  course,  for  then  results  might  be  compared. 

Notes  should  be  concise,  rarely  in  essay  form,  and  as  far  as 
possible  in  outline  and  tabular  form.  There  are  occasions 
where  copying  of  illustrations  is  desirable,  provided  that  the 
student  plainly  indicates  the  source. 

The  figures  in  the  Applied  Biology  were  chiefly  taken  from 
standard  biological  books  and  have  been  credited,  as  far  as 
possible,  to  the  books  used  in  copying.  Teachers  should  refer 
to  these  figures  for  more  complete  descriptions  than  are  given 
in  text  and  legends  in  the  text-book.  The  authors  are  of  the 
opinion  that,  as  a  rule,  the  well-known  figures  from  standard 
biological  works  are  to  be  preferred  to  new  ones  that  might 
be  made  to  order.  Moreover,  good  outline  figures  are  usually 
far  more  significant,  as  illustrations  correlated  with  the  text, 
than  photographs  could  be,  although  the  latter  might  have  an 
ornamental  value. 


APPENDIX   II 

BIOLOGICAL  BOOKS  AND  PAMPHLETS 

TEACHERS  who  wish  suggestions  regarding  the  selection  of 
biological  books  are  referred  to  the  following  authors :  Ganong, 
1910,  Chapter  VIII  is  an  excellent  account  of  botanical  books. 
A  less  complete  chapter  is  in  the  1899  edition.  Bigelow,  1904, 
Chapter  X,  has  a  selected  list  of  books  in  zoology,  physiology, 
bacteriology,  general  biology,  and  evolution.  Many  excellent 
books  published  since  1904  are  named  in  this  Manual.  Lloyd, 
1904,  Chapter  X,  has  a  list  of  botanical  books. 

Methods  of  Teaching  Biological  Sciences 

GANONG,  W.  G.,  The  Teaching  Botanist.  Macmillan.  1899. 
Revised,  1910.  $1.25.  (Indispensable  to  teachers  of  botany 
and  most  of  it  useful  for  zoologists.) 

Lloyd,  F.  E.,  and  Bigelow,  M.  A.,  The  Teaching  of  Biology  in 
Secondary  Schools,  Longmans,  1904,  $1.50.  Part  I,  Teaching 
of  Botany  and  Nature-Study,  by  Lloyd;  Part  II,  Teaching  of 
Zoology  and  Physiology,  by  Bigelow. 

Concerning  Government  Pamphlets 

Many  bulletins  and  other  agricultural  circulars  mentioned  in 
this  Manual  may  be  obtained  free  by  writing  to  the  United 
States  Department  of  Agriculture,  Washington,  D.C.,  or  to 
any  congressman.  Give  numbers  and  titles  of  pamphlets 
wanted.  Farmers'  Bulletins  are  now  sold  at  five  cents  each,  but 
the  Department  and  congressmen  have  free  copies. 

A  bibliography  classified  for  the  use  of  teachers  is  published 
by  the  United  States  Department  of  Agriculture  in  Circular  19, 
Division  of  Publications. 

A  monthly  list  of  agricultural  publications  is  sent  regularly 
to  all  applicants.  It  records  both  new  and  reprinted  pamphlets. 

99 


100  TEACHER^   MANUAL   OF  BIOLOGY 

Many  of  the  more  elaborate  publications  of  biological  value 
are  for  sale  by  the  Superintendent  of  Documents,  Washington, 
D.C.  A  list  of  such  publications  may  be  obtained  from  UK 
Department  of  Agriculture. 

There  are  many  valuable  pamphlets  published  by  various 
colleges  of  agriculture  and  state  experiment  stations;  e.g.,  tin- 
famous  Cornell  Nature-Study  Leaflets.  Since  in  most  <; 
these  local  bulletins  cannot  be  widely  distributed  and  the  supply 
is  limited,  it  has  seemed  best  to  give  in  this  Manual  referent •> 
to  those  publications  which  are  likely  to  be  kept  in  print  for 
the  next  five  or  ten  years. 

Books  on  General  Biology  for  Teachers 

NEEDUAM,  J.   G.     General    Biology.      Ithaca,    N.Y..    < 'oinstock 

Co.,  1910.     $2.00. 

PARKER,  T.  J.     Elementary  Biology.     Macmillau.     1897.     $2.00. 
SEDGWICK,  W.  T.,  and  WILSON,  E.  B.     General  Biology.     Holt. 

1895.     $1.75. 

Books  on  Botany  for  Teachers 

COULTER,  J.  M.,  BARNES,  C.  R.,  and  COWLES,  H.  C.  Text-Book 
of  Botany  for  Colleges.  3  vols.  A.  B.  Co.  1911. 

CURTIS,  C.  C.  Nature  and  Development  of  Plants.  Holt.  He- 
vised,  1910.  $2.50. 

GANONG,  W.  G.  Laboratory  Course  in  Plant  Physiology.  Holt. 
$1.75. 

Gray's  New  Manual  of  Botany.  By  Robinson  and  Fernald. 
A.  B.  Co.  7th  ed.,  1908.  $2.50.' 

STRASBURGER  and  others.  Text-Book  of  Botany.  Macmillan. 
$5.00. 

See  also  chapter  on  botanical  books  in  Ganong's  Teaching 
Botanist,  1911. 

Books  of  Zoology  for  Teachers 

See  list  given  by  Bigelow,  1904,  pp.  419-421.  The  following 
are  more  recent  zoologies. 

DREW,     G.    A.     Laboratory     Manual    of    Invertebrate    Zoology. 

Saunders,  1907.     $1.25. 
HEGNER,   R.   W.     Introduction   to  Zoology.     Macmillan.     1910. 

$1.90. 


BIOLOGICAL   BOOKS  AND:  PAMPHL^T^  10] 

OSBORN,  H.     Economic  Zoology.     Macmillan.     1908.     $2.00. 

SEDGWICK,  A.  Students'  Text-Book  of  Zoology.  2  vols.  Mac- 
millan. Vol.  I,  $4.50;  II,  $5.00. 

WEYSSE,  A.  W.  Synoptic  Text-Book  of  Zoology.  Macmillan. 
1904.  $2.25. 

Books  of  Physiology,  Hygiene,  and  Bacteriology  for  Teachers 

ALLEN,  W.  H.     Civics  and  Health.     Ginn.     1909.     $1.25. 

HALLIBURTON,  W.  D.  Handbook  of  Physiology.  (23d  edition  of 
Kirkes'),  Blakiston.  1911.  $3.00. 

HOUGH,  T.  and  SEDGWICK,  W.  T.  Human  Mechanism.  (Part 
I,  "Elements  of  Physiology,"  Part  II,  "  Hygiene  and  Sanita- 
tion" are  also  published  separately.  $1.25  each.)  Ginn. 
1906.  $2.00. 

HOWELL,  W.  H.  Text-Book  of  Physiology.  Saunders.  1905. 
$4.00. 

HUXLEY,  T.  H.  Lessons  in  Physiology.  Revised  by  F.  S.  Lee. 
Macmillan.  1900.  $1.10. 

JORDAN,  E.  O.     General  Bacteriology.     Saunders.     1910.     $3.00. 

MARSHALL,  C.  E.     Microbiology.     Blakiston.     1911.     $2.50. 

MARTIN,  H.  N.  Human  Body,  Advanced  Course.  Holt.  Re- 
vised, 1910.  $2.50. 

PYLE,  W.  L.  Personal  Hygiene.  Saunders.  Revised,  1906. 
$1.50. 

Arranging  some  books  of  physiology  in  order  of  difficulty  for 
students,  the  list  runs  :  Martin's  Human  Body,  Briefer  Course 
(for  high  school) ;  Hough  and  Sedgwick  or  Huxley-Lee  (for 
early  college  years) ;  Martin's  Advanced  Course  or  Halliburton 
for  a  college  course  including  histology,  embryology,  and 
physiology  ;  and  Ho  well  for  most  advanced  pure  physiology. 

Text-Books  of  Biology,  Botany,  Zoology,  Physiology  for  High 
Schools 

The  following  books  should  be  in  high-school  libraries.    Others 
are  cited  by  Ganong,  1910,  Lloyd,  1904,  and  Bigelow,  1904. 

ANDREWS,  E.  F.,  Practical  Course  in  Botany.      A.  B.  Co.  1911. 

$1.25. 

ATKINSON,  G.  F.,  Botany.     Holt.     1910.     $1.25. 
ATKINSON,  G.  F.,  First  Studies  of  Plant  Life.    Ginn.   1901.     $.60. 
BAILEY,  L.  H.,  Beginners1   Botany   ($,60),   Lessons  with  Plants 

($1.10),  Botany  ($1.10).     Macmillan. 


!<!-2.       -      YKAf.'IlSRS*   MANUAL   OF  niOLn>,  y 


BEHGEN,   J.  Y.tf  Foundations   of   Hninni/,    1901   ($1.  .">());    , 

Hals  of  Botany  ($1.50);    Element*  <>f  Hotany  ($1.30).    (Jinn. 
BERGEN,  J.  Y.,  and  CALDWELL,  O.  W.     Practical  Botany.     Ginn. 

1911.     $1.50. 

CLUTB,  W.  N.     Laboratory  Botany.     Ginn.    1909.     $.75. 
COLTON,  B.  P.,  Zoology.     (Text-book  and  practical  book  in  one 

or  two  volumes.)     Heath.     1903.     $1.20. 
COULTER,    J.    M.,    Plant    Relations    ($1.10);     Plant    Structures 

($1.20)  ;  Plant  Studies  ($1.25)  ;  Text-Book  of  Botany  ($1.25)  ; 

Appleton. 
DAVENPORT,  C.  B.  and  G.  C.      Introduction  to  Zoology,  1900. 

Elements  of  Zoology,    1911    ($1.20);  Macmillan. 
DAVISON,  ALVIN,  Practical  Zoology.  A.  B.  Co.     1906.      $1.00. 
EDDY,  W.  H.,  General  Physiology  and  Anatomy.  A.  B.  Co.  $1.20. 
HODGE,  C.  F.,  Nature  Study  and  Life.     Ginn.     1902.     $1.50. 
HOLTZ,  F.  L.,  Nature  Study.    Scribners.     1908.    $1.50. 
HUNTER,  G.  W.,  Essentials  of  Biology.  A.  B.  Co.  1911.      $1.25. 

(Revision  of  Elements  of  Biology.) 
JORDAN,  D.  S.,  and  Heath,  H.,  Animal  Forms.     Appleton,  1902. 

$1.10. 
JORDAN  and  KELLOGG,  V.  L.,  Animal  Life.     Appleton.     1900. 

$1.20.     Animal  Life  and  Animal  Forms  in  one  vol.,  Animals, 

$1.80.     Animal  Studies.     $1.25. 

KELLOGG,  V.  L.,  Elementary  Zoology.     Holt.     1901.     $1.35. 
LEAVITT,  R.  G.,  Outlines  of  Botany.     A.  B.  Co.     $1.00.     (Really  a 

revised  Gray's  Lessons.) 
LINVILLE,  H.  R.  and  KELLY,  H.  A.,  Text-Book  of  Zoology.     Ginn. 

1906.     $1.50.     Laboratory  Guide,  $.35. 
MARTIN,   H.  N.,    Human   Body,   Briefer   Course.     (Revised   by 

Fitz).     Holt.     $1.25. 
OSTERHOUT,   W.  J.   V.,   Experiments   with   Plants.     Macmillan. 

1905.     $1.25. 

PEABODY,  J.  E.,  Studies  in  Physiology.     Macmillan,  $1.10. 
PEABODY  and  HUNT,  Plant  Biology.     Macmillan.    1912. 
RITCHIE,   J.   W.,    Primer   of    Hygiene    ($.40)    Primer    of  Sani- 

tation   ($.50).     (Intended  for  reading  in  grammar  schools.) 

World  Book  Co.,  Yonkers. 
SHARPE,  R.  W.,  Laboratory  Manual  for  Solution  of  Problems  in 

Biology.     A.  B.  Co.  1911.     $.75. 


APPENDIX  III 

BIOLOGICAL  LABORATORY  EQUIPMENT,  MATERIALS,  AND 
METHODS 

Laboratories  and  Equipment 

REFERENCES:  Lloyd,  1904,  Chapter  IX,  Ganong,  1910, 
Chapter  VI;  1899,  Chapter  V,  Bigelow,  1904,  409-416.  See 

also  sets  of  School  Science  and  Mathematics,  1901  to  present  date ; 
and  Journal  Applied  Microscopy,  1898-1903. 

Dealers  in  laboratory  equipment  are  named  by  above  authors, 
and  they  advertise  in  Science,  School  Science  and  Mathematics, 
and  Nature-Study  Review. 

Dealers  in  Laboratory  Equipment  and  Supplies 

The  author  is  best  acquainted  with  the  following  firms  who 
manufacture  or  deal  in  microscopes  and  other  laboratory  appa- 
ratus and  supplies.  The  following  abbreviations  indicate  the 
lines  of  stock  prominently  carried  by  each  dealer  :  A,  biological 
laboratory  apparatus  ;  C,  chemicals  ;  C  P,  apparatus  for  chemis- 
try and  physics  ;  F,  laboratory  furniture ;  G,  laboratory  glass- 
ware ;  M,  microscopes,  lenses,  and  accessories  (such  as  slides  and 
cover-glasses)  ;  O,  optical  apparatus  (such  as  stereopticons, 
field-glasses).  In  writing  for  information,  specify  the  lines  you 
are  interested  in  and  ask  for  special  catalogs. 

Bausch  &  Lomb  Optical  Co.,   Rochester,  N.Y.     Branches  in 

many  cities.    A,  C,  G,  M,  O,  CP. 
Spencer  Lens  Co.,  Buffalo,  N.Y.    A,  G,  M,  O. 
E.  Leitz,  18th  St.,  New  York  City.    A,  G,  M,  O. 
Central  Scientific  Co.,  Chicago,  111.    A,  C,  CP,  F,  G,  M,  O. 
Eimer  &  Amend,  18th  St.  and  Third  Ave.,  New  York  City.    A,  C, 

CP,  G,  M. 
Cambridge  Botanical  Supply  Co.,  Cambridge,  Mass. 

103 

v 


TEA' ill  i;-'    MANUAL   OF  BIOLOGY 

Kny-Scheerer  Co.,  Ninth  Avo.,  New  York  City.    A,  O,  M,  &p«  - 

cialists  in    natural  history    specimens,    skeletons,    models, 

charts. 
Williams,  Brown  &  Earle,  Chestnut  St.,  Philadelphia.    A,  C,  (i, 

M,  O. 
Ward's    Science    Establishment,    Rochester,    N.Y.      Prepared 

specimens  of  all  kinds. 
Whitall,  Tatum  &  Co.,  Barclay  St.,  New  York  City.    G. 

In  many  cities  there  are  local  dealers  who  sell  at  regular  prices 
the  goods  of  any  manufacturing  firms.  Some  local  dealers  known 
to  the  author  are  as  follows  :  Philadelphia  :  A.  H.  Thomas  Co., 

E.  Pennock  ;  St.  Louis  :  H.  Heil  Chemical  Co. ;    Pacific  Coast : 
J.    Caire,    San   Francisco,    Braun-Knecht-Heimann    Co.,    San 
Francisco,  F.  W.  Braun  Co.,  Los  Angeles. 

Biological  Specimens  for  Study 

Directions  for  collecting  and  names  of  some  dealers  are  given 
by  Qanong,  1899,  Chapter  VI ;  1910,  VII  (botanical) ;  Lloyd, 
1904,  222-228  (botanical);  and  Bigelow,  1904,  Chapter  IX 
(zoological). 

Dealers 

A.  A.  Sphung,  N.  Judson,  Ind.  (frogs). 

F.  J.  Burns,  W.  South  Water  St.,  Chicago  (frogs). 

Louis  Knoll  &  Sons,  Washington  Market,  New  York  (crayfish, 
lobsters,  clams,  etc.) . 

Shawmut  Market  Co,  State  and  Lake  Sts.,  Chicago  (crayfish  in 
autumn). 

Blackford's  Market,  Fulton  Market,  New  York  City  (crayfish, 
crabs,  clams,  frogs). 

Brimley  Bros.,  Raleigh,  N.C.  (animal  specimens). 

Kny-Sheerer  Co.,  New  York  City  (living  and  preserved  speci- 
mens for  class  work). 

Western  Biological  Supply  Co.,  Station  A,  Lincoln,  Neb.  (mi- 
croscopic slides.  Living  and  preserved  biological  mate- 
rials). 

F.  Z.  Lewis,  Boys'  High  School,  Brooklyn,  N.Y.  (microscopic 
preparations). 

Marine  Biological  Laboratory,  Woods  Hole,  Mass,  (preserved 
marine  organisms) . 


EQUIPMENT,   MATERIALS,  AND  METHODS       105 

H.  M.  Stephens,  Dickinson  College,  Carlisle,  Penn.   (preserved 
marine  specimens) . 

Write  to  the  professor  of  biology  at  the  nearest  college  for 
names  of  local  dealers. 

Methods  of  Laboratory  Work 

REFERENCES:   Ganong,  1899,  Chapter  III,  or  1910,  Chapter 
IV.     Bigelow,  1904,  Chapter  III. 


APPENDIX   IV 
A  YEAR'S  COURSE  IN  BIOLOGY 

MANY  teachers  and  principals  have  inquired  concerning  the 
place  of  the  Applied  Biology  in  high-school  education,  and  this 
has  suggested  the  possible  value  of  a  re"sum6  of  arguments  for 
and  against  a  year's  course  of  biology  in  place  of  separate  courses 
in  botany  and  zoology. 

The  four-year  curricula  of  most  high  schools  is  so  arranged 
that  there  is  great  need  of  a  one-year  course  of  biological  science 
adapted  for  the  great  majority  of  students.  Here  are  the  facts 
in  support  of  this  proposition :  (a)  It  is  generally  admitted  that 
four  science  courses,  one  for  each  year,  offer  the  maximum  amount 
of  science  desirable  for  the  average  secondary-school  student. 
The  fact  is  that  the  great  majority  of  students  in  American 
schools  get  less  than  three  science  courses  in  four  years  of  high 
school.  (6)  Chemistry,  physics,  botany,  zoology,  human 
physiology,  earth  science  —  a  total  of  six  —  are  the  sciences 
which  must  be  taken  into  consideration.  Moreover,  many 
schools  have  "general  science"  or  "elementary  science"  in  ihe 
first  year,  (c)  There  are  two  possible  solutions,  namely, 
election  or  concentration :  Election  means  that  students  will 
fail  to  get  a  broad  outlook  on  the  general  field  of  natural  science, 
and  possibly  they  may  omit  all  biology.  Concentration  of  the 
biological  work  into  one  course  would  leave  biology,  physics, 
chemistry,  earth  science  —  one  course  for  each  year  of  the  high 
school;  or  a  choice  of  three  of  the  four  when  "general  science'' 
occupies  the  first  year,  (d)  A  course  in  biology  would  great ly  in- 
crease the  number  of  students  who  have  some  knowledge  of 
both  the  animal  and  plant  aspects  of  life.  With  separate  courses 
in  botany  and  zoology,  a  large  number  of  students  who  have 
time  to  study  botany  must  omit  zoology,  or  vice  versa.  This 
is  very  unfortunate,  especially  because  both  animals  and  plants 
are  of  such  great  interest  as  biology  applied  to  human  life.  More- 
over, the  separate  courses  in  botany  and  zoology  do  not  properly 

106 


A  YEAR'S  COURSE  IN  BIOLOGY  107 

develop  the  physiological  and  bacteriological  phases  in  relation 
to  human  life. 

The  objection  raised  by  some  teachers  who  oppose  a  course 
in  biology  is  that  botany  and  zoology  have  developed  into  two 
sciences  which  are  so  distinct  as  to  demand  separate  teaching. 
No  doubt  this  statement  is  true  in  those  all-too-numerous  col- 
leges where  research  for  the  few,  rather  than  liberal  biological 
training  for  the  many,  prevails ;  but  high-school  teachers  should 
recognize  that  many  college  courses  of  technical  botany  and 
zoology  are  aimed  at  advanced  courses  and  research  and  do  not 
adequately  present  the  great  ideas  or  principles  of  the  life  sciences 
with  reference  to  the  needs  of  the  average  well-educated  citizen. 
Both  high-school  and  college  teachers  of  biology  need  to  study 
more  seriously  the  problems  of  teaching  an  introductory  biological 
course  with  reference  to  the  needs  of  general  education,  rather 
than  as  a  preparation  for  advanced  technical  courses.  Viewed 
in  this  way,  the  teaching  of  introductory  biological  science 
in  either  school  or  college  becomes  the  selection  and  presentation, 
not  so  much  of  the  facts,  as  of  the  greatest  ideas  or  principles 
which  may  be  drawn  from  organized  study  of  a  series  of  plant 
and  animal  forms.  These  greatest  ideas  of  biology  are  those 
which  involve  both  animals  and  plants  in  their  mutual  relation- 
ships and  in  their  bearing  upon  human  life,  and  as  separate 
sciences  neither  botany  nor  zoology  can  adequately  present  them. 
Herein  is  a  decided  advantage  of  a  course  of  biology  over  any 
introductory  courses  of  either  botany  or  zoology.  No  botany 
or  zoology  course  now  in  use  as  the  introductory  biological 
course  in  either  high  schools  or  colleges  contains  as  many  im- 
portant facts  and  ideas  for  general  education  as  are  found  in 
courses  of  general  biology.  Therefore  the  separate  courses  of 
botany  or  zoology  are  entirely  inadequate  for  that  vast  majority 
of  students  who  can  take  but  one  course  and  that  the  introduc- 
tory, in  biological  science. 

From  numerous  high  schools  and  colleges  has  come  the  pro- 
test that  botany  and  zoology  (especially  the  special  books) 
are  so  vastly  rich  in  materials  that  even  with  a  full  year  for  each 
they  cannot  be  "finished."  The  writer  confesses  that  he  has 
not  been  able  to  get  into  sympathy  with  this  protest.  Why 
should  we  want  students  to  "finish"  botany  or  zoology  in  one 
year,  or  even  in  five?  We  do  not  "finish"  other  subjects  in 
high  school  or  in  college ;  but  on  the  contrary,  we  select  materials 
for  well-rounded  courses,  some  short  and  some  long.  Of  course, 


108  '/'/•;.  I  '//A'/.'V    M.\  \  I  AL   OF  BIOLOGY 


we  cannot  complete  a  wide  survey  of  any  of  the  l>i 
sciences  in  a  single  year,  but  there  are  great  possibilities  of 
selection  when  our  outlook  on  science  for  the  average  citizen 
is  that  of  liberal  education  as  distinguished  from  technical 
education.  If  one  takes  any  current  high-school  or  colle^<- 
book  on  zoology  or  botany  and  goes  through  the  pages  criti<  all\ 
questioning  each  paragraph  from  the  point  of  view  of  education 
for  general  culture  and  information,  he  is  amazed  at  the  amount 
of  detailed  matter  which  has  no  obvious  relation  to  general 
education.  Eliminating  such  material  of  questionable  value. 
there  is  not  left  a  superabundance  of  the  essentials,  the  great 
ideas,  of  the  two  phases  of  the  science  of  ife  needed  for  making 
a  single  course  which  to  the  average  educated  citizen  would  be 
more  valuable  than  either  botany  or  zoology  studied  without 
reference  to  its  sister  science.  And  we  must  remember  that 
the  sister  sciences  when  presented  in  separate  courses  cannot 
both  be  elected  by  numerous  students  in  high  schools  and  colleges. 
Looking  at  biology  from  this  point  of  view  of  liberal  education 
and  laying  entirely  aside  the  practical  problems  of  curricula, 
which,  as  indicated  above,  are  certainly  tending  to  limit  tin- 
study  of  biology  to  a  single  year  for  the  average  student,  a  year'- 
course  in  biology  is  best  because  it  forces  selection  of  the  val- 
uable materials  and  develops  most  highly  the  important  value- 
of  biological  science  in  general  education. 

The  above  discussion  has  touched  only  the  informational 
side  of  the  values  of  biological  study.  Limitation  of  space 
forbids  appropriate  discussion  of  the  scientific  discipline  derivable 
from  the  study  ;  but  on  this  point  there  is  no  argument  against 
the  year  in  biology  and  in  favor  of  botany  and  zoology  taught 
independently.  On  the  contrary,  we  may  expect  to  get  more 
valuable  scientific  discipline  from  the  study  of  the  more  important 
subject-matter  which  would  be  concentrated  into  a  year  of 
biology.  The  only  possible  objections  to  this  view  are  those 
centered  around  the  obsolete  idea  that  science  study  must  be 
carried  far  into  detail  in  order  to  give  the  best  scientific  dis- 
cipline. This  may  be  true  from  the  research  standpoint;  but 
as  applied  to  the  everyday  life  of  the  average  cultured  citizen 
the  results  of  study  of  biological  details  in  schools  and  colleges 
have  been  far  from  satisfactory.  In  all  science  teaching  we  seem 
to  be  moving  rapidly  toward  introductory  courses  which  so 
present  information  worth  having  that  the  discipline  gained 
will  lead  to  greater  application  in  practical  life.  Therefore, 


A  YEAR'S  COURSE  IN  BIOLOGY  109 

so  far  as  so-called  scientific  discipline  is  concerned,  we  may 
confidently  assert  that  any  possible  advantage  of  one  type  of 
biological  course  over  another  will  be  in  the  one  which  offers  the 
most  valuable  subject-matter,  and  this  is,  beyond  serious  doubt, 
a  course  which  presents  the  general  facts  and  ideas  regarding 
living  things  —  in  short,  a  course  of  biology. 


INDEX 


The  figures  given  below  refer  to  pages,  not  sections,  in  this  Manual.  Teachers 
who  refer  directly  from  the  Applied  Biology,  or  from  the  table  in  the  appendix  of 
the  Introduction  to  Biology  should  follow  the  section  numbers  rather  than  those  of 
pages.  Teachers  who  use  this  Manual  in  connection  with  other  text-books  should 
also  examine  the  corresponding  sections  in  the  Applied  Biology. 


Absorption,  21. 

Adaptations,  of  seed-plants,  40. 

Agassiz,  method  of,  9. 

Albuminoids,  85. 

Alcohol,  teaching  concerning,  91- 

93. 

Algse,  37,  52. 

Alternation  of  generations,  45. 
Amoeba,  59. 
Animals,  study  before  plants,   16, 

23,  38;    interest  in,  25. 
Annelids,  63. 
Anterior,  82. 
Antitoxins,  57. 
Assimilation,  11. 

Bacteria,  55-57. 

Barium-water,  13. 

Bean  plant,  26. 

Biology,  of  animals,  16 ;  of  plants, 
23  ;  year's  course,  105-108. 

Birds,  72. 

Blood,  22. 

Books,  on  birds,  72  ;  on  botany,  99- 
101 ;  crustaceans,  66  ;  evolution, 
94;  heredity,  95;  hygiene,  91, 
93;  insects,  69;  mammals,  73; 
physiology,  99-101 ;  seed-plants, 
41 ;  sex-education,  78-80 ;  zo- 
ology, 99-101.  See  also  sections 
devoted  to  various  groups  of 
animals  and  plants. 

Botany,  beginning,  23-25;  short 
course,  38. 


Breathing,  12,  31; 

human,  89. 
Butterflies,  67. 


of  plants,  15 ; 


Calyx-adnate  theory,  49. 

Carbohydrates,  33,  84. 

Carbon  dioxide,  13,  33  ;  from  plants, 

35. 

Castor  oil  seed,  42. 
Chemistry,  4. 
Chordata,  36,  71. 
Cicada,  68. 

Circulation,  in  capillaries,  19. 
Classification,  1,  37. 
Ccelenterates,  61. 
Control  experiments,  14. 
Corn  grain,  43. 
Crayfish,  65. 
Cruelty  to  animals,  19. 

Demonstrations,  methods,  7;    ex- 
amples of,  17. 
Diet,  88. 

Diffusion-shells,  31. 
Digestion,  86. 
Disinfectants,  56. 
Dissection,  17. 
Dorsal,  26,  82. 
Drawings,  96. 

Earthworm,  63. 
Echinoderms,  64.  • 
Elements,  in  human,  85 ;  in  yeast, 
53-55. 


Ill 


112 


INDEX 


Embryology,  22;  of  plants,  45; 
vertebrate,  73-80. 

Energy,  87. 

Epicotyl,  43. 

Epidermis,  frog's,  20  ;  leaf,  20  ;  hu- 
man, 86. 

Ergot,  53. 

Evolution,  books,  94. 

Experiments,  methods,  14. 

Fats,  85. 

Fehliug's  solution,  84. 

Fern,  51. 

Fertilization,  flowers,  45 ;  double,  46. 

Fertilizers,  soils,  32. 

Flies,  69. 

Flowering  plants,  23,  49. 

Flowers,  27 ;  tubular,  48. 

Food,  plant,  15,  32;    human,  83- 

85,88. 
Forestry,  44. 
Frog,  as  type,  16;  practical  notes, 

18,  19;   embryology,  22. 
Fruits,  49. 
Fungi,  52. 

Gelatin  media,  55. 
Generalizations,  simplified,  10. 
Germ  diseases,  57. 
Germination,    use    of    term,    28, 
methods,  29;    physiology  of,  44. 
Grafting,  44. 
Grasshopper,  67. 
Growth,  11. 

Heat,  internal,  89. 

Heredity,  books,  95. 

Homologies,    36;      of     phut     s.  x 

organs,  46. 
Human,  73,  81-90. 
Hydra,  61. 
Hygiene,    teaching,    83 ;     personal, 

91-93 ;  public,  93. 
Hypocotyl.  43. 


Insects,  67-69. 
Laboratory  work, 


equipment, 


102  ;  supplies,  102-104  ;  methods, 
104. 


Leaves,  physiology  of,  34. 
Lepidoptera,  67. 
Life-activities,  9. 
Lime-water,  12. 
Linnaeus,  36. 

Mammals,  73. 
Matter,  4-6. 
Metabolism,  36. 
Microscope,  use,  20. 
Mollusks,  70. 
Mosquitoes,  69. 
Moss,  52. 
Mushrooms,  53. 
Myriapoda,  67. 

Note-books,  8,  06. 
Nutrients,  84. 

Order   of   study,    16,    23,    3s.    31», 

58. 
Osmosis,  21,  29;  apparatus,  30,  31, 

86. 

Ovary,  inferior,  40. 
Ovules,  and  egg-eell.s,  27. 
Oxygen,    in    respiration,    '21  ;     in 

plants,  35. 

Paramecium,  59. 

Parchment  tubing,  31. 

Pasteur's  solution,  53. 

Phanerogams,  23. 

Photosynthesis,  33. 

Physiology,      beginning.      21  ;       of 

plants,  29;    human,  sl-90. 
Plants,   study  before   animals,    16, 

33.  38. 

Pollen-grains  and  sperm-cell.-    27. 
Preparations,  for  microscope.  20. 
Propagation,  plant,  50. 
Protein   test,    84;     oxidation,    87; 

diet,  88. 
Prothallia,  51. 
Protoplasm,  14. 
Protozoa,  58-60. 
Pruning,  44. 

Reproduction,  73-80. 
Respiration,  12,  21 ;  see  also  Breath- 
ing. 


INDEX 


113 


Reviews,  need  of,  82. 
Roots,  26. 

Saprophytes,  33. 

Sciences,  2 ;    in  high  school,  105- 

108. 

Seed-dispersal,  50. 
Seed-plants,  38-50 ;    emphasis  on, 

39. 

Seeds,  bean,  27,  41. 
Sex-instruction,  73-80. 
Sex-organs  in  plants,  46. 
Skin,  89. 
Snail,  70. 

Soil,  29 ;  bacteria  in,  56. 
Species,  number  of,  37,  69. 
Specimens  for  study,  103. 
Spiders,  66. 
Sponges,  61. 
Spore-plants,  51-57. 
Squash,  seeds  and  species,  41. 


Squid,  70. 

Stamens,  as  "male"  orga  s,  46. 
Starch,  test,  34 ;   in  leaves,  34. 
Stems,  fluids  in,  32 ;   growth,  44. 
Suction,  use  of  term,  31. 
Sugar,  in  leaf,  34,  85. 
Supplementing  text-books,  42. 

Tadpoles,  19. 

Temperance  instruction,  92. 

Transpiration,  32. 

Ventral,  27. 
Vertebrata,  36,  71-80. 
Vivisection,  17. 
Volvox,  52. 

Water,  in  soil,  29. 
Worms,  62. 

Yeast,  54. 


rrvHE  following  pages  contain  advertisements  of  a 
few  of  the  Macmillan  books  on  kindred  subjects. 


ELEMENTS  OF  PHYSICS 

BY  HENRY    CREW 

PROFESSOR  OF  PHYSICS,  NORTHWESTERN  UNIVERSITY 

REVISED  BY  FRANKLIN    T.  JONES 
TEACHER  OF  PHYSICS,  UNIVERSITY  SCHOOL,  CLEVELAND 

Cloth,  ismo,  illustrated,  xiv  +  435  pages,  $1.10  net 

This  text  presents  only  those  elements  of  physics  which 
can  be  easily  comprehended  by  the  average  high  school 
pupil  of  sixteen.  It  constantly  appeals  to  the  everyday 
experience  of  both  boys  and  girls,  and  shows  them  Physics 
as  a  science  of  daily  life.  Without  overemphasis,  it  reveals 
the  historical  development  of  the  study.  Moreover,  it  is 
arranged  in  such  logical  sequence  that  the  science  appears 
in  its  true  nature  as  an  orderly  unit,  not  as  a  series  of  dis- 
connected chapters  on  Mechanics,  Sound,  Heat,  Light,  etc. 

In  the  belief  that  the  best  teaching  must  include  suitable 
drill-work,  abundant  material  for  a  many-sided  review  is 
provided  in  the  Appendix,  in  the  form  of  a  collection  of 
questions  selected  from  examination  papers  of  schools  all 
over  the  country.  The  Appendix  also  contains  special 
hints  on  the  solution  of  typical  numerical  problems,  though 
all  complicated  mathematical  formulae  have  been  excluded 
as  unsuitable  for  an  elementary  text  on  Physics.  The 
underlying  principles  of  the  book  are  simplicity  and  prac- 
ticality. 


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Publishers  64-66  Fifth  Avenue  New  York 


CHEMISTRY,  An  Elementary  Textbook 


By  WILLIAM  CONGER  MORGAN,  PH.D., 
Assistant  Professor  of  Chemistry  in  the  University 
of  California,  and  JAMES  A.  LYMAN,  PH.D., 
Professor  of  Chemistry  in  Pomona  College 

Cloth,  i2mo,  illustrated,  xiv  -f  429  pages,  $1^5  net 
This  is  an  unusually  attractive  and  stimulating  text,  written  by  two 

college  instructors,  both  of  whom  have  taught  in  secondary  schools. 
The  underlying  motive  of  the  book  is  outlined  in  the  preface  as 

follows: 

"  In  the  preparation  of  this  text  the  authors  have  been  actuated 
by  the  feeling  that  the  student  should  never  be  allowed  to  get  the 
idea  that  chemistry  is  a  science  that  dwells  inside  laboratories  and 
acts  chiefly  in  beakers  and  test  tubes.  He  should  be  conscious  con- 
tinually of  its  presence  about  him  on  every  hand,  in  nature,  in  the 
home,  and  in  the  whirring  world  of  industry.  He  should  know  that 
in  the  past  chemistry  has  been  one  of  the  great  forces  which  have 
determined  the  civilization  and  development  of  mankind,  and  should 
feel  certain  that  in  the  future  its  importance  will  not  be  less.  Con- 
sequently, the  authors  have  tried  to  bring  out  the  humanistic  side 
of  the  science,  to  use  as  far  as  possible  that  material  which  is  laden 
with  intense  human  interest  because  of  its  significance  to  the  race." 

As  this  practical  end  demands,  an  intelligent  understanding  of  the 
fundamental  principles  of  chemistry  is  insisted  upon.  The  text  re- 
peatedly points  out  the  way  in  which  reaction  after  reaction,  as  it  ap- 
pears during  the  development  of  the  subject,  illustrates  some  principle 
already  explained.  Special  helps  will  be  found  in  the  well-planned  dia- 
grams and  tables,  admirable  illustrations,  and , interesting  topics  sug- 
gested for  discussion.  The  method  of  the  book  is  inductive,  and  its 
constant  aim  is  to  encourage  the  student  to  think  from  fact  to  theory. 


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INTRODUCTION    TO    GENERAL    SCIENCE 

WITH  EXPERIMENTS 

BY  PERCY   E.    ROWELL,  B.  Sc. 

Cloth,  i2mo,  xxix  +  302  fages,  $.  75  net 

The  Introduction  to  General  Science  was  written  to  supply  the 
well-defined  demand  in  our  early  secondary  classes  for  a  text  in 
this  new  and  important  subject.  The  author,  an  experienced 
and  successful  teacher  in  California  schools,  has  been  equally 
successful  as  a  pioneer  in  the  general  science  textbook  field. 
Avoiding  the  temptation  natural  in  such  a  course,  — specializa- 
tion in  some  particular  branch  —  he  has  properly  outlined  the 
subject  as  a  demonstration  of  the  interrelation  of  all  sciences. 
An  understanding  of  the  fundamental  principles  involved  in  the 
study  will  stimulate  the  pupil  to  further  scientific  attainment. 

The  book  gives  a  broad,  adequate  view  of  the  general  field  of 
science.  The  elements  of  physics  and  chemistry  receive  partic- 
ular emphasis,  but  biology,  physiography,  and  several  phases  of 
applied  science  are  duly  considered.  The  subject  matter  is 
divided  into  short  sections,  which  makes  it  possible  for  the  pupil 
to  learn  at  one  time  all  important  facts  relating  to  one  subject. 
A  number  of  the  ninety  or  more  laboratory  exercises  in  the  book 
are  entirely  new.  Reference  reading  is  encouraged,  and  lists  of 
carefully  selected  standard  reference  books  are  suggested. 
Those  teachers,  however,  who  do  not  care  to  take  up  detailed 
work  of  this  sort,  may  give  a  satisfactory  course  by  using  in  con- 
nection with  the  book  only  certain  listed  bulletins  of  the  United 
States  Government. 

In  matter  and  method  the  book  is  admirably  adapted  for  use 
in  schools  differing  widely  in  size,  local  conditions,  and  labor- 
atory facilities.  It  is  teachable. 


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Elements  of  Agriculture 

BY   G.    F.    WARREN 

Professor  of  Farm  Crops  and  Farm  Management,  New 
Yprk  State  College  of  Agriculture,  at  Cornell  University 

Cloth,  I2mo,  456  pages,  $1.10  net 

CONTENTS 

INTRODUCTION  — THE  IMPROVEMENT  OF  PLANTS  AND  ANIMALS—  PROPA- 
GATION OF  PLANTS  — PLANT  FOOD  — THE  SOIL— MAINTAINING  THE 
FERTILITY  OF  THE  LAND— SOME  IMPORTANT  FARM  CROPS  — EN- 
EMIES OF  CROPS  —  SYSTEMS  OF  CROPPING  — FEEDS  AND  FEEDING  — 
THE  HORSE  — CATTLE  — SHEEP  — SWINE— POULTRY  — FARM  MAN- 
AGEMENT—THE FARM  HOUSE  — THE  FARM  COMMUNITY  — APPENDIX. 

The  Elements  of  Agriculture  is  the  work  of  an  experienced 
instructor  with  the  editorial  assistance  of  Professor  L.  H.  Bailey. 
In  both  subject  matter  and  method  of  presentation,  the  author  has 
carried  out  as  far  as  possible  the  recommendations  of  the  com- 
mittee on  methods  of  teaching  agriculture  of  the  Association  of 
American  Colleges  and  Experiment  Stations.  The  laboratory  and 
supplementary  work  is  clearly  outlined,  there  is  an  abundance  of 
questions  for  study  and  review,  and  —  a  desideratum  too  often 
overlooked  in  agricultural  texts  —  the  reading  lists  are  full  and  in- 
clude the  most  recent  publications,  a  full  bibliography  being  given 
in  the  Appendix.  There  are  two  hundred  text  illustrations  and 
fourteen  full-page  plates.  The  subject  as  thus  presented  does  not 
demand  any  special  preparatipn  on  the  part  of  the  teacher ;  the 
usual  knowledge  of  elementary  botany  and  chemistry,  and  a  fair 
familiarity  with  farm  operations  will  suffice  to  conduct  the  work. 

In  addition  to  its  use  in  high  school  work,  the  book  is  suffi- 
ciently exhaustive  to  be  used  in  normal  schools,  academies,  and 
for  brief  courses  in  colleges,  as  well  as  for  farmers'  reading  circles 
and  general  library  use. 

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